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General EBSD Bibliography - Search By Letter W


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195 records found


1.    Wadsack, R., R. Pippan, et al. (2003). "Structural refinement of chromium by severe plastic deformation." Fusion Engineering and Design 66-68: 265-269.

In the present study, pure chromium (99.97%) has been deformed by high pressure torsion (HPT). The deformation has been performed clearly above the ductile to brittle transition temperature (320-390 c configu C) of the material in its recrystallized condition and at room temperature. Specimens with different degrees of deformation have been produced. A reduction of grain size from ≈ 80 µm to the submicrometer region with typical structural sizes between 50 and ≈ 500 nm has been found by examinations in the scanning electron microscope (SEM) by means of back scattered electrons (BSE) images and by electron back scatter diffraction (EBSD) measurements. The thermal stability of the microstructures has been investigated after annealing the samples in vacuum for 10 h at 500, 600 and 700 enhanceme C. Furthermore, micro hardness measurements have been carried out. The hardness after an applied degree of deformation of 25.8 (von Mises) at room temperature of the deformed sample has been about four times higher than the hardness of the undeformed material. After the heat treatment at 700 formance C, the hardness remains about two times higher.




2.    Wagner, F., N. Bozzolo, et al. (2002). Some Remarks About the Processing of Automatic EBSD Orientation Measurements in View of Texture Determination. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

EBSD measurements often aim to determine precisely the ODF. The paper intends to define the best measurement and post-processing conditions as well as those of the ODF calculation. It is illustrated with data from some hexagonal alloys.




3.    Wagner, F., N. Bozzolo, et al. (2002). "Evolution of recrystallisation texture and microstructure in low alloyed titanium sheets." Acta Materialia 50: 1245-1259.

The evolution of microstructure and crystallographic texture in low alloyed titanium sheets, initially deformed by 80% cold rolling, are investigated at different stages of the recrystallisation process. Optical and transmission electron microscopies, as well as X-ray diffraction and EBSD are used to provide information about recrystallisation mechanisms and kinetics. Orientation Density Function (ODF) differences are used to quantitatively compare recrystallised and deformed states. The main texture features of the deformed state evolve only slightly during the primary recrystallisation. The major changes in texture result from secondary recrystallisation or grain growth. Primary recrystallisation can be roughly separated into two stages. The first one is very fast and corresponds to the appearance of new grains in about 80% of the material volume. The second stage is more sluggish. It corresponds to the disappearance of the so-called “white grains”, which did not twin during deformation due to their stable orientation near {φ1 = 0°, Φ = 45°, φ2 = 0°}. Recovery is an important mechanism throughout the process and deformation heterogeneities must be taken into account for a good understanding of the recrystallisation in titanium.




4.    Wagner, F., P. Obringer, et al. (1996). The Variation of Microstructure in a Polycrystalline Silicon Ingot. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




5.    Wahab, A. A. and M. V. Kral (2005). "3D analysis of creep voids in hydrogen reformer tubes." Materials Science and Engineering A 412(1-2): 222-229.

An ex-service hydrogen reformer tube composed of Fe–0.45% C–25% Cr–35% Ni–1.0% Si–1.5% Nb–1.0% Mn (approximate wt.%) was examined via serial sectioning and 3D reconstruction to characterize creep voids in terms of their size, location, and surrounding precipitates. In addition, electron backscatter diffraction (EBSD) technique was used to investigate any crystallographic influence on the location of these voids. Observations in 3D show that void distribution is not uniform in terms of size, shape, and location. Most of the voids are oblong and occur at grain edges and corners. In addition, all observed voids were in contact with the Cr-rich M23C6 precipitates. EBSD results showed that 80% of the M23C6 precipitates surrounding these voids have an irrational crystallographic orientation relationship (OR) with the austenite matrix, contrary to the expectation that grain boundary precipitates nearly always obtain rational OR with respect to one adjacent grain.




6.    Wall, M., A. J. Schwartz, et al. (2001). "A high-resolution serial sectioning specimen preparation technique for application to electron backscatter diffraction." Ultramicroscopy 88: 73-83.

A high-resolution serial sectioning specimen preparation technique is described for acquisition of electron backscatter diffraction (EBSD) data. The primary objective is to develop a method to reproducibly remove a controlled thickness of material from a polycrystalline Ta sample while producing quality surfaces for EBSD orientation imaging. This is integrated with the ability to accurately measure the amount of material removed with each iteration and experimentally register the ensuing EBSD scans. To facilitate enhanced accuracy of this method, a metrology device containing high-precision etching patterns is fabricated using standard lithographic techniques. This metrology device allows for the sub-micron measurement of the serial section slice thickness and approximately 1 mm registration accuracy of each EBSD scan.




7.    Wang, B. F. and Y. Yang (2006). "Dynamic recrystallization in adiabatic shear band in α-titanium." Materials Letters 60(17-18): 2198-2202.

The microstructure and microtexture in adiabatic shear bands (ASBs) on the titanium side of the titanium/mild steel explosive cladding interface are investigated by means of OM, SEM/EBSD and TEM. The highly elongated subgrains and fine equiaxed grains with low dislocation density are observed in ASBs. Recrystallization microtextures (282/O), sur, 54nt, cross, 0kers, org), (60nomers, a, 90itiators, 0s leading) and (28ite lamel, 34anocompos, 30aterials) are formed within ASBs. According to the misorientation distribution, the grain boundaries in ASBs are geometrical necessary boundaries (GNBs) with high-angles. The temperature in the ASBs is estimated to be about 776 similar to 1142 K (0.4 similar to 0.6 Tm). Based on the rotational dynamic recrystallization (RDR) mechanism, the fine equiaxed grains in the core of ASBs are formed during the deformation processing. These results indicate that the dynamic recrystallization take place in ASBs. Based on 2005.




8.    Wang, G., S. D. Wu, et al. (2002). Study of the GBCD for the Grain Growht Areas on Pure Cu Samples Extruded by Means of ECAE. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

Most of the submicron crystalline materials processed by means of equal channel angular extrusion (ECAE) exhibit inherent grain size stabilities up to reasonably high temperatures just as the nanocrystalline materials. But when pure Cu single crystal samples were processed by means of ECAE, grain growth occurs at room temperature in some parts of the samples. The microstructures in these areas are analyzed by the electron backscatter diffraction (EBSD) and electron channeling contrast (ECC) techniques. When the magnification rate is rather low, the Grain Boundary Character Distribution (GBCD) results show that the small-angle and sigma-3 twin boundaries are the two main grain boundary types, the small-angle grain boundaries being a little more frequent than the sigma-3 twin boundaries. When larger magnification rates are chosen, the results are similar, except theat the percentage of sigma-3 twin boundaries exceed that of the small-angle grain boundaries. The GBCD results show similar characteristics to those of the recrystallized conventional coarse-grained metallic materials.




9.    Wang, G., S. D. Wu, et al. (2003). "Microstructure, texture, grain boundaries in recrystallization regions in pure Cu ECAE samples." Materials Science and Engineering A 346(1-2): 83-90.

By means of equal channel angular extrusion (ECAE) pure Cu single crystal samples were processed down to the submicron scale. In some parts of the samples, recrystallization occurs at room temperature. The recrystallization mechanism was analyzed by SEM-EBSP and SEM-ECC techniques. The grain boundary character distribution (GBCD) and the orientation distribution function (ODF) of the regions undergoing recrystallization were computed. The results show that the nuclei can be formed at the intersections of two different shear bands, and the microstructures and the grain boundary characters in these locations contribute to growth of recrystallized nuclei. The recrystallized grains had grown according to the Feltham's mechanism.




10.    Wang, G., S. Wu, et al. (2003). "Microstructural Characteristics by EBSD and ECC in ECAE Processed Pure Cu Samples." Advanced Engineering Materials 5(8): 593-597.

Equal channel angular extrusion (ECAE) is a process in which a workpiece undergoes very severe plastic strain without any concomitant change in its cross-sectional dimensions. This process has received considerable attention in recent time as it has the capability of introducing an ultrafine grain size - in the submicrometer or nanometer range - in large-grained materials. In our own experiments, the pure Cu single-crystal samples were ECAE-processed to investigate their fatigue properties. But it was shown that, when the samples were stored at room temperature, the grain size in some parts of the samples became larger than that in other parts. After some time, the size of the growing grains in these samples became so large that the local orientation and grain boundary distributions could be investigated applying electron back-scattering diffraction associated with scanning electron microscopy (SEM-EBSP) to these locations. In these places, the microstructures of the samples were also observed by the electron channeling contrast technique in scanning electron microscopy (SEM-ECC). The results showed that the change in grain size could be attributed to the occurrence of recrystallization. As it developed in only a few parts of the samples, it was appropriate to analyze the relationship between recrystallization and structural characteristics in the ECAE-processed pure Cu samples




11.    Wang, J., Z. Liu, et al. (2005). "EBSD analysis of the microstructure of al interconnects and their electromigration reliability." Chinese Journal of Stereology and Image Analysis 10(4): 218-220.

The grain structure, the crystallographic orientation and the grain boundary character of Al interconnects were measured by using electron backscatter diffraction technique. Processing and annealing influenced the microstructure and the mean failure time due to electromigration (EM) for the Al interconnects. During the annealing, the grain size increased, leading to the development of a near bamboo structure, with an increase in the {111} texture and in the fraction of low angle grain boundaries, resulting in the improvement in EM reliability of the AL interconnects.




12.    Wang, M.-m., W.-j. Lu, et al. (2005). "An EBSD and TEM study on the microstructural evolution of in situ synthesized (TiB + TiC)/Ti matrix composites during superplastic deformation." Materials Transactions 46(8): 1833-1838.

Microstructures of in situ synthesized (TiB + TiC)/Ti matrix composites after superplastic deformation at 980° C with a strain rate of 5 * 10-3s-1 have been studied. Optical microscope (OM) and scanning electron microscopy (SEM) observations indicate that the mean grain size decreased. Electron back-scattered diffraction (EBSD) and transmission electron microcopy (TEM) observations reveal that the density of sub-grain boundaries and high angle grain boundaries increased during superplastic deformation, clearly indicating that dislocation sliding and climbing are important processes during superplastic deformation. The experiment results indicate the superplastic deformation is controlled by grain boundary sliding and dislocation motion, which is consistent with the result deduced from activation energy.




13.    Wang, P. H., M. Veeraraghavan, et al. (2002). "Massive-Parent Interphase Boundaries and Their Implications on the Mechanisms of the a to YM Massive Transformation in Ti-Al Alloys." Metallurgical and Materials Transactions A 33A(No. 8): 2353 - 2371.

The massive-parent interphase boundaries associated with the a-to-YM massive transformation in a Ti-46.5 at. pct Al alloy were studied. Special experiments were performed to arrest the transformation at an early stage. Orientation relationships (ORs) between the YM and parent a(retained as a2) phases were determined using electron backscattered diffraction (EBSD) in a scanning electron microscope and by electron diffraction, and the interphase boundaries were characterized by two-beam bright-field/weak-beam dark-field (WBDF) transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The results reveal that the YM nucleates at grain boundaries generally with a low-index Burgers orientation relation and a coherent interface with one parent grain, but grows into the adjacent grain with a high-index/irrational orientation relation. The growth interfaces between the two phases are denerally free of misfit dislocations or other defects and consist of curved parts as well as planar facets, whose macroscopic habit planes are of generally high-index/irrational orientation and deviate substantially from the close-packed planes. On an atomic scale, the growth interfaces are sometimes found to be faceted along { 111 } planes, as well as along other planes, with closely spaced steps, but are concluded to be incoherent with respect to the parent grain into which growth occurs. The implications of these results on the nucleation and growth mechanisms associated with the a-to-YM massive transformation are discussed. In particular, the nature of the interphase boundaries and their realtion to whether growth occurs by a ledgewise motion of the interfaces or by continuous growth are addressed.




14.    Wang, P. H., P. S. Ho, et al. (1998). "Electromigration Study of Al Low Dielectric-Constant Polymer and Al/SiO2 Dioxide Line Structures." Journal of Applied Physics 84(11): 6007-6016.




15.    Wang, P. T., W. H. Van Geertruyden, et al. (2003). Formation of surface recrystallization of Al-Mg-Si alloy during extrusion. Metallurgical Modeling for Aluminum Alloys. Proceedings from Materials Solutions Conference 2003. 1st International Symposium on Metallurgical Modeling for Aluminum Alloys, Pittsburgh, PA, USA, ASM International.

The formation of peripheral coarse grain structure of Al-Mg-Si alloy in extrusion is characterized by employing high temperature lab-scale indirect extrusion tests with minimum friction involved. Extremely large strains, strain rates, and elevated temperatures are imposed on extrudates with relative ease of handling. Butt and extrudate samples are analyzed using optical microscopy and EBSD techniques to determine the depth of surface recrystallization and grain morphology including misorientation, grain size and texture. Since the transition between coarse grain and as-extruded grain regions is very distinct by the abrupt changes of grain appearance, an energetic approach based on Gibbs free energy and internal state variable approach is proposed to represent a recrystallization front criterion. To track heterogeneous deformation history from surface to sub-surface of extrudates, a finite element flow analysis to track the front criterion is suggested. The proposed recrystallization front criterion is sensitive to the drag force imposed by dispersoid, and thermal and deformation histories.




16.    Wang, P., D. Veeraraghavan, et al. (2003). Interphase boundaries in the alpha to gammaM massive transformation in Ti-Al alloys. Electron Microscopy: Its Role in Materials Science. Mike Meshii Symposium. Proceedings of a Symposia, San Diego, CA, USA, TMS - Miner. Metals & Mater. Soc.

The massive-parent phase orientation relations and interphase boundary structures associated with the alpha to gammaMmassive transformation in a Ti-46.5 at.% Al alloy were studied using a combination of electron back scatter diffraction (EBSD) and electron diffraction, and conventional and high resolution transmission electron microscopy (HRTEM). The results reveal that the gammaM nucleates at grain boundaries generally with a low-index Burgers orientation relation and coherent interface with one parent grain, but grows into the adjacent grain with a high-index/irrational orientation relation. The growth interfaces between the two phases are generally free of misfit dislocations or other defects and consist of curved parts as well as planar facets whose macroscopic habit planes are of generally high-index/irrational orientation and deviate substantially from the close-packed planes. On an atomic scale the growth interfaces are sometimes found to be faceted along {111} planes, as well as along other planes, with closely spaced steps, but are concluded to be incoherent with respect to the parent grain into which growth occurs. The nature of the interphase boundaries and their relation to the nucleation and growth mechanisms associated with the alpha to gammaM massive transformation is discussed.




17.    Wang, R., J. Gui, et al. (2002). "EBSD and TEM study of self-accomodating martensites in Cu75.7Al15.4Mn8.9 shape memory alloy." Acta Materialia 50(7): 1835-1847.

Morphologies and orientation relationships of martensites in Cu75.7Al15.4Mn8.9 shape memory alloy were studied for the first time by means of electron backscatter diffraction (EBSD) technique, transmission electron microscopy (TEM) and phenomenological calculation. The martensite was identified to be an 18R1 type monoclinic one with its b angle very close to 90°. Each plate group of martensite variants consists of four variants A, B, C and D showing characteristic spear- and fork-like morphologies. Variants A and C (and equivalently B and D) are twin-related with respect to the (1 2 8) plane of the 18R1martensite, which is transformed from, and nearly parallel to (with an error of only 0.60°), a (0 1 1)P plane of the parent phase. Variant-pair A–D (and equivalently B–C) is twin related with respect nearly to the (2 0 20)18R plane, which is transformed from a (1 0 0)pparent plane. However, the discrepancy between these two planes, (2 0 20)18R and (1 0 0)p, is 2.01°, larger than that (0.60°) between and (0 1 1)P. Therefore, this twin boundary prefers to consist microscopically of several low index planes, forming a zigzag morphology, as observed by TEM. Phenomenological calculation of the cubic D03 parent phase to monoclinic M18R1 martensite transformation revealed that although the magnitude of the shape strain produced by the martensitic transformation is calculated to be rather large (m=0.2005), the average shape deformation of each self-accommodating plate group is rather small. And the total average shape deformation for six plate groups becomes nearly zero, except for a small volume contraction. The angles between the basal plane of the 18R1 martensite and the twin planes of different variant-pairs in a plate group, determined from EBSD and TEM experiments, are consistent with phenomenological calculations.




18.    Wang, S. (2004). "Welding of single crystal nickel-base superalloys." JOM 56(11): 282.

Single crystal nickel-base superalloys have been used as gas turbine blade materials for the last few decades due to their excellent high temperature mechanical properties and corrosion resistance. The high costs associated with replacement blades calls for new repair solutions to extend their life cycles, and welding is an efficient process to repair the blades that are worn or damaged during service. Feasibility of both fusion welding and solid state welding is determined by the ability to produce desired microstructures, which yield the required service properties. Therefore, numerous welding trials and mechanical tests must be employed to determine the optimum welding conditions and method. Weldability of single crystal PWA1484 is investigated in this paper in terms of various welding parameters and directions. Pre and post welding heat treatments are applied to the material to optimize the welding conditions. The crack morphology is observed and microstructure development is analyzed using scanning electron microscopy (SEM), optical microscopy (OM) and indexing electron backscattered diffraction (EBSD) patterns. Several potential difficulties of welding single crystal, such as the susceptibility of hot cracking and stray grain formation, which are related to weld pool shape and grain growth orientation, are discussed. Micro-hardness testing is also carried out to characterize the localized microstructural features and mechanical properties of autogenously welded PWA1484.




19.    Wang, S. C., M. Aindow, et al. (2003). "Effect of self-accommodation on a/a boundary populations in pure titanium." Acta Materialia 51(9): 2485-2503.

An analysis of the shape strains produced by the martensitic beta -> alpha transformation in pure titanium indicates that there are three likely slip systems which could operate to give the complementary shear. The greatest degree of self-accommodation of the shape strains was given by clusters of three variants of alpha grains and two kinds of clusters were identified. In one kind of cluster, the high-angle grain boundaries (HAGBs) formed between adjacent laths of different variants would all be 1120 /60 deg -type, and in the other kind they would all be 10 5 5 3 /63.3 deg -type. Analysis of the frequency distributions for misorientation angles in pure Ti using electron backscattered diffraction confirms a strong preference for the formation of these two types of HAGBs, with 78% of the HAGBs being classed as such, as compared to 36% which one would expect for a random distribution of variants. A statistical analysis of nucleation, which accounts for the observed frequencies of the different types of HAGBs, is proposed.




20.    Wang, S. C., M. Browne, et al. (2005). "Determination of the fatigue fracture planes of Co-Cr-Mo biomedical alloys using electron backscatter diffraction." Journal of Microscopy 217(2): 118-121.

Electron backscatter diffraction on a scanning electron microscope has been utilized to acquire crystal orientation information around faceted fatigue cracks in a Co-Cr-Mo alloy for medical implants. The faceted fracture planes are unambiguously determined as {111} planes.




21.    Wang, S. C., M. J. Starink, et al. (2005). "Grain Structure and Texture Development During ECAP of Two Heat-Treatable Al-Based Alloys." Reviews on Advanced Materials Science 10(3): 249-255.

The microstructures of a spray-cast Al-7034 (Al-Zn-Mg-Cu) alloy and an Al-2024 (Al-Cu-Mg) alloy were studied using electron back-scatter diffraction (EBSD) after processing through equal-channel angular pressing (ECAP). The EBSD results demonstrate there is a relatively rapid increase in the fraction of low-angle boundaries during the initial ECAP passes and a subsequent more gradual increase in the fraction of high-angle grain boundaries in subsequent passes. The crystallographic textures and their rotations during ECAP were analysed through EBSD.




22.    Wang, S. C., Z. Zhu, et al. (2005). "Estimation of dislocation densities in cold rolled Al-Mg-Cu-Mn alloys by combination of yield strength data, EBSD and strength models." Journal of Microscopy 217(2): 174-178.

Al-Mg-Cu-Mn alloys have been developed for the packaging industry, in which large cold-working deformations are normally applied that can produce high dislocation densities. In this study, we present a simplified model for the yield strength contributions and apply that to obtain the dislocation densities by determining the orientation factors, which can be obtained via the crystal information of electron backscatter diffraction (EBSD). One alloy subjected to three cold-rolling reductions (10%, 40% and 90%) has been analysed by EBSD, and the density of dislocations are estimated using the strengthening model. This assessment suggests that dislocation densities by the Taylor model are roughly consistent but slightly lower than those determined by transmission electron microscopy.




23.    Wang, S. S., K. Wu, et al. (2004). "Development and evolution of biaxial texture of rolled nickel tapes by ion beam bombardment for high Tc coated conductors." Physica C 407: 95-102.

High quality YBa2Cu3O7-x films on metallic substrates with high critical current densities well over 106 A/cm2 can be prepared by the rolling assisted biaxially textured substrates (RABiTS) method. Nickel or its alloys have been used as biaxially textured substrates formed through a specific rolling and high temperature annealing procedures. In this paper, we report a newly developed process for developing biaxial texture in rolled Ni tape by argon ion beam bombardment. It is named the ion-beam structure modification (ISM) process. In the ISM processed Ni foils, X-ray diffraction x scans showed the full width-half maximum (FWHM) value of the (2 0 0) peak was 5.7°. And the electron back scattering diffraction (EBSP) analysis based on scanning electron microscopy showed good {1 0 0} <0 01> cubic orientation and the mean grain size was determined as about 25 µm. The texture evolution of rolled Ni foils during ISM process is reported also. For ISM process, local temperature elevation and distribution arises from the ion bombardment, coupled with anisotropic incident ion penetration and propagation as a result of channeling effects in the metal lattice, are expected to play the major roles in the development of grain reorientation in the Ni foil. Due to the simplicity and efficiency of the ISM process, the technique shows a great promise for application in the industrial scale production of long-lengths of superconductor tapes.




24.    Wang, T. T., B. L. Adams, et al. (1990). "Development of Orientation Coherence in Plane-Strain Deformation." Metallurgical Transactions A 21(8): 2223-2236.




25.    Wang, T. T., P. R. Morris, et al. (1990). "Characterization of the Morphological and Lattice Orientational Microstructure of As-Cast Aluminum Ingot." Metallurgical Transactions A 21(8): 2265-2275.




26.    Wang, W., L. Feng, et al. (2005). "Grain Boundary Character Disctribution (GBCD) of cold-rolled Pb-Ca-based alloy during annealing." Chinese Journal of Stereology and Image Analysis 10(4): 215-217.

The grain boundary character distribution (GBCD) of a cold rolled Pb-0.1%Ca-1.5%Sa0.026%Al alloy during annealing was investigated by means of electron back scatter diffraction. The results indicate straight Σ3 coherent twin boundaries of over 60% (all values are given as a length fraction of the total boundary length) are introduced in the alloy when annealed at 220°C for 72 hours after cold rolling to 10% reduction in thickness. Such boundaries are not distributed in a network of general high angle boundaries (HABs) and the GBCD is not optimized. However, for annealing at 270°C for 7 minutes of samples cold rolled to 30%, apart from Σ3 boundaries of over 65%, a fair amount of Σ9 and Σ27 coincidence site lattice boundaries were also developed. These Σ9 and Σ27 boundaries along with the large number of curved S3 boundaries are located in a network of HABs and the GBCD is optimized.




27.    Wang, X. M., X. L. He, et al. (2002). "Refining of intermediate transformation microstructure by relaxation processing." ISIJ International 42(12): 1553-1559.

The influence of RPC (relaxation-precipitation-controlling phase transformation) processing parameters on the microstructure was studied by thermo-simulation for a low carbon Nb and To containing microalloyed steel. The semi-quantitative statistic work of the packet size was carried out by the aid of optical microscope. TEM, EBSD and SEM were applied to investigate the microstructure refinement, precipitation, the evolution of crystal defects configuration and their interaction during the relaxation. The results demonstrate that the steel is composed of ultra-fine bainite/martensite composite microstructure, and the microstructure could be refined markedly by RPC processing. The best thermo-simulation process for refinement in this experiment is deformation by 30% at 850 deg C, and then relaxing at this temperature for 60 to 200 s. Increasing the reduction ratio from 30 to 60% or decreasing the deformation temperature to 800 deg C would cause the optimized relaxation time to become shorter, and increasing the deformation temperature to 900 deg C would cause the refinement effect to be weaker. It is also indicated that the nucleation, growing and coarsening of precipitates, and the dislocations polygonizing occur during the relaxation. Both two processes could be helpful to refine the intermediate transformation microstructure, and when these two processes corporate and promote each other, the optimized processing is obtained.




28.    Wang, X., E. Brunger, et al. (2002). "The role of twinning during dynamic recrystallization in alloy 800H." Scripta Materialia 46(12): 875-880.




29.    Wang, Y. N. and J. C. Huang (2003). "Comparison of grain boundary sliding in fine grained Mg and Al alloys during superplastic deformation." Scripta Materialia 48: 1117-1122.

The surface topography resulting from grain boundary sliding (GBS) in warm-extruded AZ61 sheets was investigated after tensile superplastic loading, and compared with previous examinations on Al base alloys. GBS was observed to prevail from the very initial stage; ~60% of total strain was contributed by GBS due to the high fraction (88%) of high angle boundaries in AZ61, distinctly different from the case of Al alloys.




30.    Wang, Y., H. Kimura, et al. (2005). EBSD-AFM hybrid analysis of fatigue slip system and crack initiation in polycrystalline metal under cyclic torsional loading. Proceedings of the 2005 International Symposium on Micro-NanoMechatronics and Human Science. The Eighth Symposium Micro- and Nano-Mechatronics for Information-Based Society, Nagoya, Japan, IEEE.

In the present study, we utilize both EBSD and AFM methods with replica technique to investigate the active slip systems and fatigue crack initiation behavior in face-centered cubic polycrystalline metal, austenitic stainless steel, SUS3I6NG, under cyclic torsional loading. The surface of a fatigued specimen was investigated with the hybrid EBSD-AFM method. The analysis on the active slip systems of those grains based on Schmid' plastic theory, shows that in polycrystalline metal most grains possess the plane with the largest Schmid factor value as their primary slip plane. Fatigue cracks on the free surface were observed by scanning electron microscopy (SEM) and were classified into 4 types: GB (grain boundary), TB (twin boundary), SB (slip band) and TC (transcrystalline). The lengths and angles between the cracks and axis of those 4 types of crack were also measured respectively. The results of crack density distribution in comparison with the earlier research on tensional fatigue show that under low loading level TC cracks dominate the initiation stage regardless of the loading mode. By using the EBSD-AFM hybrid method, the condition of initiation of SB cracks was discussed with 4 parameters: h, depth of intrusion vertical to the surface; S, slip displacement; SA, the element of slip displacement parallel to the surface; SB, the element of slip displacement vertical to the surface trace. The result indicates that SB of accumulated slip deformation takes a constant value at crack initiation.




31.    Wang, Y., J. Zhu, et al. (2000). "Application of EBSP to directional solidified Ni3Al." Intermetallics 8: 669-671.

A new method called EBSP (electron back scattered pattern) is applied to directional solidified Ni3Al alloy. The statistic of the GB that is usually implemented only in TEM can be carried out in SEM too. From OIM (orientation imaging microscopy) of both samples, the statistic of coincide site lattice (CSL) of dendrite GB can be acquired. Through the statistic, percentage of boundary in the longitudinal and transverse direction of both samples can be obtained.




32.    Wang, Z.-J., S. Tsurekawa, et al. (1999). "Relationship between Electrical Activity and Grain Boundary Structural Configuration in Polycrystalline Silicon." Interface Science 7: 197-205.

Temperature dependent electron beam induced current (EBIC) technique has been applied to investigate the electrical activities of grain boundaries (GBs) in polycrystalline silicon. The GB character, misorientation and orientation of GB plane, were analyzed using a FE-SEM/EBSP/OIM system prior to the EBIC measurements. The EBIC contrasts were found to depend in GB character; low ΣGBs showed weak contrasts compared with general GBs at any temperatures, and also demonstrated to vary at GB irregularities such as boundary steps. These results indicate that electrical properties depend on the orientation of the GB plane as well as the misorientation. On the other hand, there existed less differences in temperature dependence of EBIC contrast irrespective of GB characters.

The EBIC contrast decreased with increasing temperature, showed a minimum around 250 K, then increased again with further increasing temperature. The resulting temperature dependence of EBIC contrast probably comes from the combination of two types of recombination processes of carriers. One is related to a shallow level associated with an inherent GB structure, though the exact energy levels also would probably depend on GB structures, and the other to a deep level associated with impurities segregated at GBs, which acts as recombination center.




33.    Wangyue, Y., W. Hongmei, et al. (2003). "Dynamic recrystallization of ferrite in a low carbon steel with different minor microstructures." Acta Metallurgica Sinica (China) 39(7): 691-698.

The microstructure evolution during dynamic recrystallization and the deformation characteristics of a low carbon steel within the temperature range of 600 to 700 degrees C and a strain rate range of 10-3 to 10s-1 have been investigated by means of thermal-compression simulation test, SEM, TEM and EBSD In order to understand the effect of microstructures on dynamic recrystallization behavior, two different microstructures were adopted, which consist of ferrite plus pearlite and ferrite plus fine cementite particles respectively. The results show that dynamic recrystallization takes place in these two cases. However, in the microstructure with pearlite higher strain is needed to start recrystallization and reach the steady state, comparing with the microstructure with fine cementite particles. The measurement confirms that ferrite with smaller grain size in steady state can be obtained in microstructure with ferrite and cementite, which indicates a more significant effect of separately distributed fine cementite particles on promoting recrystallization nucleation and hindering the grain growth that of pearlite.




34.    Wanhill, R. J. H. (2004). "Innovative Failure Analysis of Ancient Silver." Materials Australia 37(3): 14.

Since 1994 we have been studying the embrittlement of ancient silver, using standard optical and Scanning Electron Microscope (SEM) metallography and fractography, and Energy Dispersive analysis of X-rays (EDX) for compositional measurements. These techniques showed there are two kinds of embrittlement, which can occur synergistically: corrosion-induced embrittlement and microstructurally-induced embrittlement. In 2003 we were able to use the EBSD (Electron Back Scatter Diffraction) equipment to examine samples from the Gundestrup Cauldron, a 2000 year old masterpiece of European Iron Age silverwork.




35.    Wanhill, R. J. H. (2005). "Embrittlement of ancient silver." Journal of Failure Analysis and Prevention 5(1): 41-54.

Ancient silver may become brittle and damaged owing to long-term corrosion and changes in the microstructure. Recognition and determination of corrosion-induced and microstructurally-induced embrittlement, and also their synergy, are important for restoration and conservation of ancient and historic silver. The types of embrittlement are described and illustrated, using examples of ancient and historic silver artefacts, including the famous Gundestrup Cauldron, a masterpiece of European Iron Age silverwork. In particular, the use of automated Electron BackScatter Diffraction (EBSD) enables improved analysis and assessment of corrosion-induced embrittlement. The knowledge obtained from detailed investigations is helpful not only in determining the best ways to restore and conserve embrittled silver objects, but also in defining the possible extent of the embrittlement problem. This is illustrated by a straightforward statistical analysis. Copyright ASM International.




36.    Wardle, S. C., B. L. Adams, et al. (1994). "Characterization of Textured Aluminum Lines and Modelling of Stress Voiding." Materials Research Society Symposium Proceedings 343: 665-670.




37.    Wardle, S. T., L. S. Lin, et al. (1994). Orientation Imaging Microscopy: Monitoring Residual Stress Profiles in Single Crystals Using and Imaging Quality Prameter, IQ. Proc. 52nd Annual Meeting of the Microscopy Society of America. G. W. Bailey and A. J. Garratt-Reed. San Francisco, San Francisco Press: 680-681.

Residual stresses are routinely calculated in polycrystalline materials from the residual strains determined by x-ray diffraction (XRD) analysis. Using XRD to determine residual stresses is a well-established technique, however it cannot be used for single crystals. This investigation develops a technique that readily monitors residual deformation profiles in single crystals. The technique is of particular interest to the aerospace industry, as it enables the effectiveness of shot-peening single crystal turbine blades to be monitered.




38.    Warnken, N., D. Ma, et al. (2005). "Investigation of eutectic island formation in SX superalloys." Materials Science and Engineering A 413-414: 267-271.

We investigated whether the nucleation of the eutectic islands in superalloy solidification occurs in the interdendritic bulk liquid or at the dendrite–melt interface. Directionally solidified samples of CMSX-4 and a model superalloy have been analysed by means of light and electron microscopy and by EBSD measurements. For some samples, the solid–melt interface has been revealed by an artificial bubble technique. Additionally, thermodynamic calculations on phase formation and nucleation work as well as phase-field simulations have been performed, using ThermoCalc and MICRESS. The results indicate a kind of epitaxial nucleation mechanism at the solid–liquid interface of the primary dendrites.




39.    Waryoba, D. R. and P. N. Kalu (2005). Deformation and Recrystallization Texture of Heavily Drawn OFHC Copper. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

Deformation and recrystallization texture has been investigated in Oxygen free high conducting (OFHC) copper wires drawn at room temperature to true strain of 2.31, and isothermally annealed at various temperatures between 150° and 750°C. Local orientations of the microstructures were measured by means of electron backscattered diffraction (EBSD) technique. While the drawn wire was characterized by a major<111> + minor<100> duplex fiber texture, recrystallization occurred at annealing temperatures between 250°C and 400°C and resulted into a major<100>+minor<111> recrystallization texture. At temperatures above 500°C, the <100> dominated recrystallization texture changed to the <111> dominated growth texture due to secondary recrystallization, which favored the <111> orientation at the expense of the <100> component.




40.    Waryoba, D. R. and P. N. Kalu (2005). Textural and Microstructural Inhomogeneities in Drawn and Annealed OFHC Copper Wire. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

This work presents the results of a study on textural and microstructural inhomogeneities that develop during annealing of heavily drawn Oxygen free high conducting (OFHC) copper wire. The wire was drawn at room temperature to a true strain of 2.31 and isothermally annealed at 750°C for annealing times ranging from 10s to 1hr. The inhomogeneity of microstructure across the wire was clearly visible as three distinct concentric regions, which were classified as: the inner core, the mid section, and the outer surface. Two texture transitions were observed. At shorter annealing time, recrystallization which originated from the mid section, resulted into a strong<100>+weak<111> duplex fiber texture. However, prolonged annealing gave rise to abnormal grain-growth that proceed from the mid section to the outer surfaces with a dominant <111> fiber component at the mid and inner region, and mixed components of <111>, <100>, and <112> at the outer surfaces.




41.    Waryoba, D. R. and P. N. Kalu (2005). Textural Inhomogeneities in Drawn and Annealed OFHC Copper Wire. EPD Congress 2005 as held at the 2005 TMS Annual Meeting, San Francisco, California, USA, Minerals, Metals and Materials Society (TMS), 184 Thorn Hill Road, Warrendale, PA USA 15086-7528.

Textural inhomogeneities have been investigated in oxygen free high conducting (OFHC) copper wire drawn at room temperature to a true strain of 2.31, and isothermally annealed at 250DGC and 750DGC for annealing times ranging from 10 s to 1 hr. Local orientations were mapped by means of orientation imaging microscopy (OIM). The microtexture of the drawn wires showed a strong <111> + weak <100> duplex fiber texture at the inner core, whereas the mid and surface regions had a comparatively weak texture. Annealing at 250DGC resulted into a recrystallization which originated from the mid section, proceed towards the surface regions and ends in the inner core. Recrystallization resulted into a strong<100>+weak<111=> duplex fiber texture. A similar textural inhomogeneity was observed during short annealing at 750DGC. However, prolonged annealing gave rise to abnormal grain-growth that proceed from the inner core to the outer surfaces with a dominant <111> fiber component at the inner region and mixed components of <111>, <100>, and <112> at the outer surfaces.




42.    Waryoba, D. R., P. N. Kalu, et al. (2005). "The Role of Orientation Pinning in Statically Recrystallized Oxygen-Free High-Conductivity Copper Wire." Metallurgical and Materials Transactions A 36A(1): 205-215.

The role of orientation pinning by neighboring grains on migrating boundaries in a statically recrystallized oxygen-free high-conductivity (OFHC) copper was investigated. Two specimens of heavily drawn OFHC copper wires deformed to true strains of 2.31 and 3.56 were annealed at 170°C and local orientations were mapped by means of the automated electron backscattered diffraction technique. Inverse pole figures, misorientation distribution functions, and grain boundary misorientations were calculated from local orientation data. In spite of annealing, the microstructure of the low-strain specimen was characterized by elongated grains, similar to the as-deformed structure, whereas the microstructure of the high-strain specimen showed a high fraction of well-defined recrystallized grains. The recrystallized grains consisted of type A grains, which mostly grew laterally with {hkl} <100> orientations, and type B grains, which generally grew axially with {hkl} <111> orientations. Type A grains were larger and of higher frequency than type B grains. The large size of Type A grains was attributed to the high frequency of the mobile boundaries with misorientations in the 40 to 50 deg range. Boundaries that were misoriented at 60 deg <111> (Σ3) were found to exert the greatest pinning effect on the growing grains. This caused recrystallized grains to grow either laterally or axially, and sometime led to "branching." A detailed analysis of the influence of the next neighbor misorientations in the perimeter of the recrystallized grains is presented.




43.    Was, G. S., V. Thaveeprungsriporn, et al. (1998). "Research Summary: Grain Boundary Misorientation Effects on Creep and Cracking in Ni-Based Alloys." JOM 50(2): 44-49.




44.    Wasilkowska, A., M. Bartsch, et al. (2004). "Plastic deformation of Fe–Al polycrystals strengthened with Zr-containing Laves phases I. Microstructure of undeformed materials." Materials Science and Engineering A 380(1-2): 9-19.

The microstructures of several Fe-rich Fe–Al–Zr alloys have been studied as a basis of investigating the mechanical behaviour, which is subject of Part II. The alloys with only low Zr contents show micro-structures with a relatively soft matrix and a hard skeleton along the grain boundaries, the latter being residual eutectics containing the matrix phase and the Zr(Fe,Al)2 Laves phase. Scanning electron microscopy, orientation imaging microscopy as well as transmission electron microscopy and diffraction are used to study the grain sizes, the orientation relationships between the grains and the phases and the crystallography of the Laves phase. With higher Zr contents above about 10 at.%, the matrix is formed by the Zr(Fe,Al)2 Laves phase.




45.    Wasilkowska, A., R. Petrov, et al. (2006). "Microstructure and texture changes in a low-alloyed TRIP-aided steel induced by small plastic deformation." ISIJ International 46(2): 302-309.

The microstructures and the textures of TRIP-assisted and Dual Phase steel in undeformed state and after 10% strain applied parallel to the rolling direction of the steel sheet were studied by optical microscopy, EBSD, TEM and XRD. It was found that the strain-induced transformation of retained austenite to martensite leads to localized deformation of ferrite close to the ferrite/martensite phase boundaries and the formation of a composite skeleton of several phases (bainite, retained austenite and martensite), clasping the ferrite grains, which thereby decrease in size. Ferrite and retained austenite deform simultaneously to minimize the local stresses at the phase boundaries, until the strain-induced martensitic transformation takes place. The compositelike strengthening behaviour in a TRIP-aided steel might be expressed by the decreasing free path of dislocations in ferrite due to the enlarging and thickening of the multiphase skeleton as plastic deformation progresses, without changing significantly the main texture components in the material.




46.    Wasnik, D. N., V. Kain, et al. (2002). "Resistance to sensitization and intergranular corrosion through extreme randomization of grain boundaries." Acta Materialia 50(18): 4587-4601.

Two grades of austenitic stainless steel, type 304 and 316L, were cold rolled to different reductions by unidirectional and by cross rolling. Subsequent solutionizing of the cold rolled samples produced noticeable textural differences in type 304, but insignificant differences in type 316L. Both the solutionized materials had however the same trend in grain boundary character distribution (GBCD): an increasing fraction of random boundaries with an increasing pre-solutionizing reduction percentage. The degree of sensitization (DOS) was measured by the double loop electrochemical potentiokinetic reactivation (DL-EPR) test in both the alloys. The susceptibility to intergranular corrosion was assessed by the standard weight loss technique (practice B, A262 ASTM) in type 304 alloy. These increased with increase in random boundary concentration, but then dropped significantly beyond a ‘critical’ concentration—a pattern observed in both the grades. Such a pattern may be explained from a balance between nucleation rate of Cr-carbides and grain boundary Cr-flux, though postulating an exact model is premature at this stage. The present study, however, demonstrates a clear possibility of remarkable improvement in DOS and IGC through extreme grain boundary randomization.




47.    Wasnik, D. N., V. Kain, et al. (2004). Effects of Overall Grain Boundary Nature on Localized Corrosion in Austenitic Stainless Steels. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.

Thermomechanical processing of type 304 and type 316L stainless steels done by (a) cold rolling to a reduction in thickness of 20 to 80 percent and (b) solution annealing to obtain a medium size of grains led to a considerable inprovement in resistance to both sensitization and intergranular corrosion. The nature of the resultant grain boundaries was examined in a scanning electron microscope using orientation imaging microscopy in electron back scattered diffraction mode. Fraction of random and special grain boundaries were established for each set of thermomechanical processing. After appropriate sensitizatrion treatments, the degrees of sensitization of these stainless steels were evaluated by double loop electrochemical potentiokinetic reactivation tests. Standard ASTM tests were used to evaluate susceptibility to intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC). These studies showed that a particular combination of thermomechanical processing led to formation of over 75 percent random grain boundaries in the steels, and this imparted resistance to sensitization and to IGC and IGSCC. This opens a new concept in grain boundary (GB) engineering of a high fraction of random GB increasing the resistance to localized corrosion like IGC and IGSCC. Textural studies were carried out with the help of X-ray and MTM-FHM software. It showed significant change of texture in type 304 stainless steel, while no change in the texture of type 316L stainless steel after cold rolling and annealing.




48.    Watanabe, T. (1994). "The Impact of Grain-Boundary-Character-Distribution on Fracture in Polycrystals." Materials Science and Engineering A 176(1-2): 39-49.




49.    Watanabe, T. (1996). Grain Boundary Engineering in Textured Materials. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




50.    Watanabe, T. (1998). Grain Boundary Architecture for High Performance Materials. Boundaries and Interfaces in Materials: The David A. Smith Symposium. R. C. Pond, W. A. T. Clark and A. H. King. Warrendale, Pennsylvania, The Minerals, Metals and Materials Society: 19-29.




51.    Watanabe, T. (1999). "Grain-Boundary Engineering for Superplastcity." Materials Science Forum 304: 421-430.




52.    Watanabe, T. (2001). "The Characterization and Control of Grain Boundary Microstructure in Polycrystalline Materials." Materia Japan 40(7): 617-622.




53.    Watanabe, T. (2002). Texturing and Grain Boundary Engineering for Materials Design and Development in the 21st Century. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

The importance of the characterization of microscale texture and grain boundary microstructures is discussed as basic knowledge of grain boundary engineering for advanced structural and functional polycrystalline materials. Some examples of recent success of grain boundary engineering for the control of brittle fracture in moylbdenum and development of superplasticity in Al-Li alloy are introduced. Most recent challenges to grain boundary engineering for ferromagnetic materials through the application of magnetic field and for nanocrystalline materials are shown to be useful and powerful for future materials design and development.




54.    Watanabe, T. and S. Tsurekawa (2004). "Toughening of brittle materials by grain boundary engineering." Materials Science and Engineering A 387-389: 447-455.

Microstructural aspects of fracture processes and the origin of the brittleness in brittle materials are discussed in connection with structure-dependent intergranular fracture. The possibility of the control of “intrinsic” and “extrinsic” brittleness in polycrystalline materials by the grain boundary engineering is proposed on the basis of the optimization of the grain boundary microstructure by using newly introduced parameters, i.e., the grain boundary character distribution (GBCD) and the grain boundary connectivity. Several examples of successful control of the brittleness achieved by the present authors and coworkers are shown for intrinsic intergranular brittleness in molybdenum, and for oxidation-induced intergranular brittleness in nickel–iron alloy and SiC. The effect of GBCD on the fracture toughness may become significant in nanocrystalline materials with high density of grain boundaries.




55.    Watanabe, T., K. Obara, et al. (2004). In-Situ Observations on Interphase Boundary Migration and Grain Growth during a/g Phase Transformation in Iron Alloys. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.

In-situ observations of α/γ phase transformation were made to study the effect of grain boundary microstructure of the generation of a new phase and the migration of a/g interphase boundaries in an Iron-4.2at.%Cr alloy. It was found that triple junctions with more random boundaries could be the primary nucleation sites, while triple junctions with low angle and low Σ coincidence boundaries did not play a role as preferential sites. The migration of a/g interphase boundaries during heating across the transformation temperature showed the two stage behaviour characterized first by a stage with a migration velocity of 0.33-0.75 µm/s and secondly a stage with 3.7-7.6 µm/s. It was also found that abnormal grain growth and a high density of Σ3 coincidence boundaries could occur in the α/bcc phase after cycling of a/g/a phase transformation.




56.    Watanabe, T., M. Yamada, et al. (1991). "Grain-Boundary Strengthening Associated with Sigma=9 Near-Coincidence Boundary in (1010) Twist Zinc Bicrystals at High-Temperatures." Philosophical Magazine A 63(5): 1013-1022.




57.    Watanabe, T., S. Tsurekawa, et al. (2005). The Control of Texture and Grain Boundary Microstructure by Magnetic Annealing. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

This paper gives an overview of our recent works on the effect of magnetic annealing, i.e. annealing in a magnetic field, on the evolution of texture and grain boundary microstructure in ultra-fine grained and nanocrystalline magnetic materials differently produced; rapidly solidified Fe-6.5mass%Si ribbons, electrodeposited nanocrystalline nickel, and nanocrystalline Fe78Si9B13 alloy ribbon crystallized from the amorphous state. It was found that the effect of magnetic annealing was powerful and useful for controlling grain growth resulting in the evolution of different types of texture and grain boundary microstructure, depending on the condition of magnetic annealing. In particular, the magnetic crystallization of amorphous Fe78Si9B13 alloy was found to be powerful for producing a nanocrystalline material with a sharp texture and a special grain boundary microstructure.




58.    Watanabe, Y., H. Eryu, et al. (2002). Evaluation of Casting Textures in Al/Al3Ti Platelet Functionally Graded Material Fabricated by a Centrifugal Solid-Particle Method. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

In this study, crystal orientation of the Al matrix in Al/Al3Ti FGMs fabricated by the cetrifugal solid-particle method was investigated by using orientation image microscopy (OIM).It was found that strong orientation of the Al3Ti platelets was developed in the FGM fabricated under large G number, which is the ratio of the centrifugal force to the gravity. Contrary to the expectation, strong texture of the Al matrix was not developed in the FGM even by solidification under strong centrifugal force. Moreover, there exists no specific relationship of crystallographical orientation between Al matrix and Al3Ti platelets. Therefore, it would be concluded that nucleation and growth of Al matrix grains keeping specific orientation relationship with the pre-existing solid platelets seem to be difficult under dynamic casting with centrifugal force.




59.    Waterschoot, T., L. Kestens, et al. (2002). "Hot Rolling Texture Development in CMnCrSi Dual-Phase Steels." Metallurgical and Materials Transactions A 33(April): 1091-1102.




60.    Watt, L. E., P. A. Bland, et al. (2004). Fabric analysis of Allende matrix using EBSD. 67th Annual Meeting of the Meteoritical Society, Rio de Janeiro, Brazil, USA.

The abundant fine-grained matrix material in chondrites has limited the application of traditional fabric analysis techniques. Instead, fabric analysis has been restricted to qualitative observations involving the large scale (>100 mu m) components of chondrites, e.g., flattened chondrules, and bulk meteorite studies using X-ray pole figure goniometry, magnetic susceptibility, and natural remnant magnetization. Due to significant advances in microscopy, it has recently become possible to analyze the 3D crystallographic orientation of the fine-grained (sub-micron) matrix material in chondrites using electron backscatter diffraction (EBSD) technique, thus allowing fabrics in these materials to be visualized for the first time.




61.    Wei, M., D. Zhi, et al. (2003). Electron back scatter diffraction and X-ray pole figure analysis of c-axis textured alpha -alumina fabricated by gel-casting. Electron Microscopy and Analysis 2003. Institute of Physics Electron Microscopy and Analysis Group Conference, Oxford, UK, Inst. of Phys. Publishing Ltd.

In the present research, c-axis textured alpha -alumina ceramics have been prepared by an alginate-based, gel-cast, doctor-blade process. The macrotexture of the alpha -alumina ceramics was analysed by X-ray pole figure measurements and the c-axis texture nature was revealed using 00.12, 10.10 and 113 pole figures. In order to examine the regional grain orientation relations (microtexture), electron back scatter diffraction (EBSD) was applied in this work. Using EBSD, the boundary misorientation distribution was obtained and analysed. Apart from the well-developed low angle grain boundaries, a large fraction of boundaries were found misoriented in the range of 50-60 degrees, implying the high possibility of forming Sigma 3 boundary in this c-axis textured a-alumina ceramic. Pole figures and inverse pole figures were also measured by EBSD patterns taken from the grains in the SEM scanned area, which confirms the c-axis texture symmetry determined by X-ray diffraction.




62.    Weidner, A. and P. Klimanek (1997). "X-ray substructure analysis in cold-rolled titanium." Materials Science and Engineering A 234-236: 814-817.

Substructure development in cold-rolled alpha -titanium was investigated by X-ray diffraction line-broadening using a methodology which takes into account the texture formation of the material. The formation of defect structures is different for various grain orientations and gives rise to significant substructure-texture correlation already at lower deformation degrees. The main reason for the line-broadening and substructure differences, respectively, observed in the texture components is obviously the orientation dependence of mechanical twinning. TEM and EBSP investigations have shown that at lower deformation degrees three different twinning systems are activated.




63.    Weiland, H. (1992). "The Determination of Long-Range Misorientations in the Microstructure of Materials." Acta Metallurgica et Materialia 40(5): 1083-1089.




64.    Weiland, H. (1994). "Applied Technology: Microtexture Determination and Its Application to Materials Science." JOM 46(9): 37-41.




65.    Weiland, H. (1994). "Microtexture Determination and its Application to Materials Science." Journal of the Minerals, Metals & Materials Society 46(9): 37-41.




66.    Weiland, H. (1997). In-situ Observation of Deformed Processes by OIM. Microscopy and Microanalysis, Cleveland, Ohio, Springer.




67.    Weiland, H. and D. P. Field (2000). Characterization of deformed microstructures by OIM. Microbeam Analysis 2000. D. B. Williams and R. Shimizu. Bristol, Institute of Physics Publishing: 193-4.




68.    Weiland, H. and J. Liu (1994). Application of microtexture analysis for materials characterization using SEM and TEM techniques. Fifty-Second Annual Meeting Microscopy Society of America/Twenty-Ninth Annual Meeting Microbeam Analysis Society, New Orleans, LA, San Fancisco Press, Inc.




69.    Weiland, H., D. P. Field, et al. (1996). Local Texture Evolution during Deformation by In-Situ OIM Analysis. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




70.    Weiland, H., J. Liu, et al. (1990). Substructure and Local Orientation Evolution of Aluminum Single Crystals during Deformation. ICOTOM 9, Avignon, France, Published in Textures and Microstructures, 14-18.




71.    Weiss, D., O. Kraft, et al. (2002). "Grain-boundary voiding in self-passivated Cu-1 at.% Al alloy films on Si substrates." Journal of Materials Research 17(6): 1363-1370.

The new generation of semiconductor metallization is based on Cu-film technology. In this paper we report on detrimental changes in surface morphology of self-passivated Cu-1 at.% Al films which were magnetron-sputtered on Si substrates. Large voids appeared at grain boundaries after annealing, oxidation at temperatures at or above 500°C, and cooling to room temperature under vacuum. Grain-orientation imaging with electron backscatter diffraction revealed that preferentially high-energy grain boundaries were voided. Contrary to reports in the literature, void growth was not prevented by the extremely clean ultra-high-vacuum conditions during film fabrication nor by the strong and very sharp grain texture. Instead, it was clearly correlated with the stable surface oxide on the self-passivated films. Void growth was not found after annealing passivation-free films such as pure Cu or unoxidized Cu or unoxidized Cu-1 at.% Al films.




72.    Weiss, S. and G. Gottstein (1998). "Grain boundary motion during high temperature cyclic deformation of high purity aluminum bicrystals." Materials Science and Engineering A 256(1-2): 8-17.

During cyclic deformation of polycrystals at elevated temperatures conspicuous microstructural changes, in particular grain boundary motion and grain boundary alignment have been reported for a variety of metallic materials. The current study addressed this issue by investigating in detail the motion of grain boundaries during cyclic deformation of bicrystals of very high purity aluminum. Bicrystals containing different types of grain boundaries were investigated to probe the influence of grain boundary character on their behaviour under cyclic loading. The displacement of the grain boundaries was recorded using optical microscopy without additional preparation. The evolution of microtexture was measured by the electron backscatter diffraction technique (EBSD) using a scanning electron microscope. During cyclic deformation a deformation structure occurred within each grain. The character of deformation structure, in particular the difference in dislocation density on both sides of the grain boundary was found to be responsible for the displacement of the boundaries. A model is proposed to explain the grain boundary motion and the grain boundary alignment during cyclic deformation of aluminum bicrystals. The relevance of these results for grain boundary behaviour in polycrystals is discussed. (Author abstract)




73.    Weiss, S., D. Ponge, et al. (1995). "Grain boundary control during high temperature low cycle fatigue." Canadian Metallurgical Quarterly 34(3): 237-241.




74.    Weiss, T. and P. Davies (2000). "Grain size measurement of aluminum wire using light microscopy and crystal orientation mapping the SEM." Trans IMF 789(2): 65-66.




75.    Wejdemann, C. and O. B. Pedersen (2004). "Atomic force microscopy of the intense slip localization causing fatigue crack initiation in polycrystalline brass." Materials Science and Engineering A 387-389: 556-559.

For wavy slip materials like copper a recent nanotheory suggests that destabilization (splitting) of edge dipolar loops (EDLs) triggers formation of intense slip lines (ISLs), which nucleate persistent slip bands (PSBs) in a thermally activated process of cyclic saturation. The nanotheory also has implications for fatigue of planar slip materials like brass, which do not display saturation. Also has implications for polycrystalline brass (Cu–30% Zn) was cyclically strained at room temperature and constant plastic strain amplitude into the secondary hardening stage associated with nucleation of intense slip bands (ISBs). After unloading from compression and electropolishing to remove surface fatigue damage the specimen was loaded to its stress amplitude in tension. Slip lines formed during the tensile half-cycle were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) and the observations were repeated after an additional compressive half-cycle.




76.    Wells, O. C. (1999). "Comparison of Different Models for the Generation of Electron Backscattering Patterns in the Scanning Electron-Microscope." Scanning 21(6): 368-371.

An electron backscattering pattern (EBSP) is formed on a fluorescent (or other) screen from the faster scattered electrons when a single-crystal region of a solid sample is illuminated by a finely focused electron beam (EB). The EBSP is very similar in appearance to the electron channeling pattern (ECP) that is obtained in the scanning electron microscope (SEM) by rocking the beam about a point on the surface of a single crystal. It has been suggested that the mechanisms that give rise to EBSP and ECP are related by reciprocity. If this is indeed the case, then the models that are used to explain them should be the same except for the direction in which the electrons travel through the specimen. The two-event "diffraction model" for EBSP (diffuse scattering followed by diffraction) fails this condition, leading to the conclusion that the "channeling in and channeling out" model for EBSP is more likely to be correct. This has been described rigorously by Reimer (1979, 1985). It is named after the title used by Joy (1994). An attempt is made here to describe this model in a simple way.




77.    Wells, O. C. (2002). Discussion of Ways to Energy-Filter the Electron Backscattering Pattern (EBSP) in the Scanning Electron Microscope (SEM). Microscopy and Microanalysis 2002, Québec City, Québec, Canada, Press Syndicate of the University of Cambridge.




78.    Wells, O. C., L. M. Gignac, et al. (2006). "Use of backscattered electron detector arrays for forming backscattered electron images in the scanning electron microscope." Scanning 28(1): 27-31.

The backscattered electron (BSE) signal in the scanning electron microscope (SEM) can be used in two different ways. The first is to give a BSE image from an area that is defined by the scanning of the electron beam (EB) over the surface of the specimen. The second is to use an array of small BSE detectors to give an electron backscattering pattern (EBSP) with crystallographic information from a single point. It is also possible to utilize the EBSP detector and computer-control system to give an image from an area on the specimen — for example, to show the orientations of the grains in a polycrystalline sample (“grain orientation imaging”). Some further possibilities based on some other ways for analyzing the output from an EBSP detector array, are described.




79.    Wen, S. and J. A. Szpunar (2005). The Correlation of Texture and Microstructure to the Corrosion Resistance of Tin Coatings. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

The influence of current density and temperature on the macrotexture, the orientation and size of grains, and the corrosion resistance of tin deposits was studied. Tin coatings with two different textures, (100) and (301) fiber textures were produced by electrodeposition at 20ºC by varying current density. At a lower current density of 100A/m2, (301) fibre was obtained. At the current densities of 100 and up to 400 A/m2, only (100) fibre texture was observed. An increase in current density leads to a decrease in grain size. At the same current density, the grain size of tin coatings increases with increased temperature. The influence of temperature (20, 40, 60 and 80 ºC) on texture is relatively negligible. The corrosion resistance of tin coatings increases with a decrease in grain size. The corrosion resistance of tin coating with (301) fibre is higher than that of tin coating with (100) fibre texture. The results suggest that texture and microstructure play an important role in controlling corrosion rate of tin based coatings.




80.    Wen, S. and J. A. Szpunar (2005). "Texture and Corrosion Resistance of Electrodeposited Tin Coatings." Archives of Metallurgy and Materials 50(1): 175-180.

Tin electrodeposition on mild steel substrates using stannous sulfate and sulfuric acid electrolyte was studied under different current densities. The morphology, macrotexture, and the orientations and sizes of individual grains were examined by FEG-SEM, x-ray texture goniometry and orientation imaging microscopy (OIM) respectively. The corrosion resistance of electrodeposited tin coatings was measured using a standard corrosion cell kit according to the ASTM standard G3-89 (94). It was found that tin coatings with two different texture, (100) and (301) fiber texture can be produced by electrodeposition at room temperature by varying current density. At a lower current density of 100A/m2, (301) fibre was obtained. At the current densities of 100 and up to 400 A/m2, only (100) fibre texture was observed. An increase in current density leads to a decrease in grain size. At a higher current density of 200 A/m2, the deposit was dense and smooth. The corrosion resistance of tin coatings increases with an increase in current density. The results suggest that operating parameters play an important role in controlling corrosion rate of tin based coatings.




81.    Wendler, B. G. and L. Kaczmarek (2005). "Oxidation resistance of nanocrystalline microalloyed γ-TiAl coatings under isothermal conditions and thermal fatigue." Journal of Materials Processing Technology 164-165: 947-953.

γ-Titanium aluminide is a promising structural material for use in automotive and aircraft applications due to its low density and creep and a relatively high strength even at the temperature as high as 1200 K. Nevertheless, its resistance to gas corrosion at high temperatures still needs to be improved. It has been proved in the work by means of SEM, EDS, EBSD, X-ray and microthermogravimetric analyses under isothermal conditions at 1173 K and thermal fatigue in the interval 373 ÷ 1173 K that a great improvement of this resistance can been achieved due to γ-TiAl-based magnetron sputtered coatings with ternary or quaternary elements from Ag, Cr, Mo, Nb, Si, Ta or W: the parabolic rate constants of the oxidation of some coatings are five orders of magnitude less than that of the bare γ-TiAl substrate.




82.    Wendrock, H., J. Richter, et al. (2001). "The determination of small areas of retained austenite in TRIP-steels using high resolution Electron Back Scattering Diffraction." Practical Metallography 38(No. 6): 314-24.




83.    Wendrock, H., K. Mirpuri, et al. (2004). Formation of electromigration defects in small damascene Cu interconnects with respect to the microstructure. Stress-Induced Phenomena in Metallization. Seventh International Workshop on Stress-Induced Phenomena in Metallization, Austin, Texas, USA, AIP.

Electromigration processes in Cu metallization are of increasing importance in microelectronics. In order to study correlations between microstructural details and localization of electromigration defects generated in narrow electroplated Cu lines, microstructure of entire line was recorded by EBSD measurements with high lateral resolution, and then electromigration test was performed in high vacuum under direct SEM observation. To do this, the lines had to be unpassivated. Short electroplated Cu lines (length of 20 and 50 mu m, width of 230 to 130 nm) were loaded at 250 degrees C and 20 MA/cm2 with in-situ-SEM observation, and EBSD maps of the line with stepsize, i.e. point distance of 20 nm were acquired before and after test. In the result, a number of hillocks were found to have grown in the vicinity of (100) grains having at least one high angle grain boundary around it. Fatal voids often formed at the cathode end and produced dielectric cracking in some cases. Furthermore, voiding started from the sidewall of interconnect trenches mostly at such places where (111) grains with high angle grain boundaries were located. Microstructure of lines down to 130 nm was analysed with respect to electromigration defects, and the electromigration behavior was found to be rather similar compared to larger lines.




84.    Wendrock, H., K. Mirpuri, et al. (2005). "Correlation of electromigration defects in small damascene Cu interconnects with their microstructure." Microelectronic Engineering 82(3-4): 660-664.

Limited reliability of interconnect material mainly due to current induced electromigration defects is one of the serious issues of actual and future microelectronic devices. The influence of interfaces and microstructure on electromigration damage in Cu interconnects became an open question again and needs further studies. In order to find correlations between microstructural details and localization of electromigration defects generated in narrow electroplated Cu lines, microstructure of entire line was recorded by electron back scatter diffraction measurements with high lateral resolution, and then electromigration test was performed in high vacuum under direct SEM observation. In the result, a number of hillocks were found to have grown in the vicinity of (1 0 0) grains having at least one high angle grain boundary around it. Fatal voids often formed at the cathode end and produced dielectric cracking in some cases. Furthermore, voiding started from the sidewall of interconnect trenches mostly at such places where (1 1 1) grains with high angle grain boundaries were located.




85.    Wendrock, H., W. Brückner, et al. (2000). "Room temperature grain growth in electroplated copper thin films." Microelectronics Reliability 40: 1304-1304.




86.    Wenk, H. R. and J. Pannetier (1990). "Texture Development in Deformed Granodiorites from the Santa-Rosa Mylonite Zone, Southern California." Journal of Structural Geology 12(2): 177-184.




87.    Wenk, H.-R. (1999). Texture analysis of earth materials. Comparison of EBSD with other diffraction techniques. Microscopy and Microanalysis, Portland, Oregon, Springer-Verlag.




88.    Wenk, H.-R. and P. Van Houtte (2004). "Texture and anisotropy." Reports on Progress in Physics 67(8): 1367-1428.

A large number of polycrystalline materials, both manmade and natural, display preferred orientation of crystallites. Such alignment has a profound effect on anisotropy of physical properties. Preferred orientation or texture forms during growth or deformation and is modified during recrystallization or phase transformations and theories exist to predict its origin. Different methods are applied to characterize orientation patterns and determine the orientation distribution, most of them relying on diffraction. Conventionally x-ray pole-figure goniometers are used. More recently single orientation measurements are performed with electron microscopes, both SEM and TEM. For special applications, particularly texture analysis at non-ambient conditions, neutron diffraction and synchrotron x-rays have distinct advantages. The review emphasizes such new possibilities. A second section surveys important texture types in a variety of materials with emphasis on technologically important systems and in rocks that contribute to anisotropy in the earth. In the former group are metals, structural ceramics and thin films. Seismic anisotropy is present in the crust (mainly due to phyllosilicate alignment), the upper mantle (olivine), the lower mantle (perovskite and magnesiowuestite) and the inner core (epsilon -iron) and due to alignment by plastic deformation. There is new interest in the texturing of biological materials such as bones and shells. Preferred orientation is not restricted to inorganic substances but is also present in polymers that are not discussed in this review.




89.    Wenk, H.-R., J. J. Donovan, et al. (1999). Texture and analysis with a digital SEM-EBSD system. Twelfth International Conference on Textures of Materials (ICOTOM 12), McGill University, Montreal, Canada, NRC Research Press.




90.    Wert, J. A. (2002). "Macroscopic crystal rotation patterns in rolled aluminium single crystals." Acta Materialia 50(12): 3127-3141.

EBSD crystal orientation measurements are presented for rolled aluminium single crystals initially having Goss, Cube and Rotated Cube orientations; (011)[100], (001)[100] and (001)[110] respectively. The orientation measurements reveal macroscopic-scale crystal rotation patterns having an amplitude that depends on initial crystal orientation. For the set of crystals studied here, the rotation amplitude increases in the order: Goss, Cube, Rotated Cube. Combining a standard model for metal flow through a converging channel with the slip system geometry in each crystal shows that the macroscopic crystal rotation pattern is coupled to the pattern of redundant strains generated during rolling. By simplifying the set of slip systems in each crystal to 2 equivalent slip systems, physical insight into the coupling mechanism between the redundant strain and crystal rotation patterns is gained. From this analysis, it can be understood that the macroscopic crystal rotation pattern reflects the macroscopic redundant strain pattern imposed on the crystal during rolling; orientation stability of a crystal has little influence on the macroscopic rotation pattern. Previously published results for the Cu crystal orientation reveal that Copper-oriented crystals, (112) [111], exhibit a net rotation, but only a small spread of orientations develops during rolling; these results are readily rationalized using the equivalent slip system method. Finally, the transition bands are shown to be bands in which the observed crystal rotations require operation of unpredicted slip systems.




91.    Wert, J. A., Q. Liu, et al. (1996). "Dislocation boundary formation in a cold-rolled cube-oriented Al single crystal." Acta Materialia 45(6): 2565-2576.




92.    Wert, J. A., X. Huang, et al. (2003). "Deformation bands in a Ý110¨ aluminium single crystal strained in tension." Proceedings of The Royal Society of London Series A 459(2029): 85-108.

An aluminium single crystal with Ý110¨ initially parallel to the tensile axis and (111) initially parallel to the front face of the crystal was elongated by 30%. Macroscopic deformation bands were visible on the broad face of the crystal after deformation. To explore the deformation-band characteristics, crystal orientations were measured using the electron-backscatter-diffraction (EBSD) technique over large areas on the front face and on a cross-section of the specimen. The measured lattice orientations demonstrate that crystal-rotation axes are not restricted to the plane normal to the tensile direction, as considered by standard analyses. An extra constraint imposed by the rectangular specimen geometry is proposed to generate lattice rotation around the tensile axis. An analysis is developed that transforms each local crystal-orientation measurement into a set of local shear amplitudes for the four critically stressed slip systems. Based on the EBSD observations and shear-amplitude analysis, three types of deformation bands are identified in the deformed crystal. On a microscopic scale, classic kink bands not exhibiting secondary slip traces and secondary slip bands are present, although these correspond to relatively minor shear-amplitude inhomogeneities. On a macroscopic scale, bands previously denoted special bands of secondary slip (SBSS) are shown to be coarse kink bands exhibiting secondary slip. SBSS are shown to have an internal structure consisting of smaller lamellar domains in which slip on (111) and (111) predominates alternately.




93.    Wessel, E., V. Kochubey, et al. (2004). "Effect of Zr addition on the microstructure of the alumina scales on FeCrAlY-alloys." Scripta Materialia 51(10): 987-992.

The effect of Zr-addition on the alumina scale formation on an FeCrAlY-alloy was studied by FEG-SEM equipped with EBSD and cathodolumines-cence detectors. The Zr imparted modifications of the alumina structure result in a higher scale growth rate, which decreases after the Zr in the bulk alloy is depleted. The effect of Zr thus depends on the Zr reservoir in the alloy i.e., on specimen thickness.




94.    West, D. A. and B. L. Adams (1997). "Analysis of Orientation Clustering in a Directionally Solidified Nickel-Based Ingot." Metallurgical and Materials Transactions A 28(1): 229-236.




95.    West, G. (2005). Characterising oxide scales using Electron Backscatter Diffraction. European corrosion congress, Lisbon, Spain.




96.    West, G. D. and R. L. Higginson (2005). "Characterisation of high temperature oxidation using electron backscatter diffraction." Materials at High Temperatures 22(3/4): 201-206.




97.    West, G. D., J. M. Perkins, et al. (2004). "Characterisation of fine-grained oxide ceramics." Journal of Materials Science 39(22): 6687-6704.

A range of high resolution techniques have been used to characterise the grain boundary segregation behaviour of rare earth (RE) doped (La, Gd, Eu and Yb) alumina and spinel. TEM based techniques (HR-TEM, HAADF STEM and EDS) have been used to study the structure and chemistry of grain boundaries. The use of a HAADF detector in STEM provides atomic number contrast and easy identification of heavy (RE) segregants. This has been used to produce high resolution RE elemental maps, showing the width of the segregated region to be less than the size of the electron probe (1 nm) for all boundaries studied. EDS showed that within a 1 nm thick boundary region (an upper limit), the RE cations would account for 10 (+or-2)% and 15 (+or-2)% of the cation total in alumina and spinel respectively. Preliminary results from ultra-high resolution STEM (probe size.0.1 nm) suggest that, in spinel, the segregated region is actually composed of a much thinner continuous monolayer of RE atoms at the grain boundary. This is consistent with HR-TEM, which showed spinel grain boundaries possessed minimal grain boundary structural disorder. AFM has been used to study the effect of RE grain boundary segregation on thermal grooving behaviour. The improvement in resolution that is achieved by operating in Tapping TM mode is shown to translate into an improved profile of the groove root. This has been used in conjunction with electron backscattered diffraction (EBSD) to examine the relationship between grain boundary geometry and misorientation. The addition of RE dopants to alumina was found to significantly increase the size of grain boundary grooves. This can be attributed to the out-diffusion of RE segregants, an effect which compromises grain boundary energy calculations for materials with grain boundary segregation. AFM and EBSD are also used to relate anisotropic tribo-chemical polishing-wear with grain orientation.




98.    West, G. D., S. Birosca, et al. (2005). "Phase determination and microstructure of oxide scales formed on steel at high temperature." Journal of Microscopy 217(2): 122-129.

Even in simple low-alloy steels the oxide scales that form during hot working processes are often a complex mixture of three iron oxide phases: haematite, magnetite and wustite. The mechanical properties, and hence descalability, are intimately linked with phase distribution and microstructure, which in turn are sensitive to both steel composition and oxidation conditions. In this study electron backscatter diffraction in the SEM has been used to characterize the microstructures of oxide scales formed on two compositions of low-alloy steel. The technique can unambiguously differentiate between the candidate phases to provide the phase distribution within the scale. This is used to investigate grain orientation relationships both within and between phase layers. It has been found that the strength of the orientational relationship between the magnetite and wustite layers is dependent on steel composition, and in particular Si content. In a low-Si (0.01 wt%) alloy only a very weak relationship was found to exist for a range of oxidation temperatures (800-1000 DGC), whereas for the higher Si (0.3 7 wt%) alloy a strong relationship was observed under the same oxidation conditions. These orientational relationships are particularly important because, in this temperature range, the majority of oxide scale growth occurs at the magnetite/ wustite interphase boundary.




99.    Wheeler, J., D. J. Prior, et al. (2001). "The Petrological Significance of Misorientations Between Grains." Contributions to Mineralogy and Petrology 141(1): 109-124.




100.    Wheeler, J., Z. Jiang, et al. (2003). "From geometry to dynamics of microstructure: using boundary lengths to quantify boundary misorientations and anisotropy." Tectonophysics 376: 19-35.

The microstructure of a quartzite experimentally deformed and partially recrystallised at 900°C, 1.2 GPa confining pressure and strain rate 10-6/s was investigated using orientation contrast and electron backscatter diffraction (EBSD). Boundaries between misoriented domains (grains or subgrains) were determined by image analysis of orientation contrast images. In each domain, EBSD measurements gave the complete quartz lattice orientation and enabled calculation of misorientation angles across every domain boundary. Results are analysed in terms of the boundary density, which for any range of misorientations is the boundary length for that range divided by image area. This allows a more direct comparison of misorientation statistics between different parts of a sample than does a treatment in terms of boundary number. The strain in the quartzite sample is heterogeneous. A 100 x 150 µm low-strain partially recrystallised subarea C was compared with a high-strain completely recrystallised subarea E. The density of high-angle (>10°) boundaries in E is roughly double that in C, reflecting the greater degree of recrystallisation. Low-angle boundaries in C and E are produced by subgrain rotation. In the low-angle range 0–10° boundary densities in both C and E show an exponential decrease with increasing misorientation. The densities scale with exp(-q/l) where λ is approximately 2° in C and 1° in E; in other words, E has a comparative dearth of boundaries in the 8–10° range. We explain this dearth in terms of mobile high-angle boundaries sweeping through and consuming low-angle boundaries as the latter increase misorientation through time. In E, the density of high-angle boundaries is larger than in C, so this sweeping would have been more efficient and could explain the relative paucity of 8–10° boundaries. The boundary density can be generalised to a directional property that gives the degree of anisotropy of the boundary network and its preferred orientation. Despite the imposed strain, the analysed samples show that boundaries are not, on average, strongly aligned. This is a function of the strong sinuosity of high-angle boundaries, caused by grain boundary migration. Low-angle boundaries might be expected, on average, to be aligned in relation to imposed strain but this is not found. Boundary densities and their generalisation in terms of directional properties provide objective measures of microstructure. In this study the patterns they show are interpreted in terms of combined subgrain rotation and migration recrystallisation, but it may be that other microstructural processes give distinctive patterns when analysed in this fashion.




101.    Wheeler, J., Z. Jiang, et al. (2004). Dynamic Recrystallization of Quartz. Second Joint International Conference on Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France, Trans Tech Publications Ltd.




102.    Wierzbanowski, K., A. Baczmanski, et al. (2005). "Residual stress and stored energy during recrystallisation in polycrystalline copper." Materials Science and Technology 21(1): 46-52.

A general X-ray multireflection method was applied to determine the stress level in deformed and recrystallised polycrystalline copper samples. Different reflections hkl were simultaneously used in the fitting procedure. The anisotropic diffraction elastic constants were calculated using the self consistent model and crystallographic texture. A significant decrease of the first order residual stresses was observed during recovery and recrystallisation. Diffraction peak widths and intensities were also examined for a few characteristic texture components during the recrystallisation process. Independently, synchrotron radiation and electron backscatter diffraction techniques were used to determine the stored energy in the examined material. The main result is that residual stress components start to reduce already before the recrystallisation process. The stored energy is strongly orientation dependent. It has the lowest value in the cubic texture component, which is dominating one in recrystalisation texture.




103.    Wierzbanowski, K., A. Baczmanski, et al. (2005). "Internal Stress and Stored Energy in Recrystallized Copper." Archives of Metallurgy and Materials 50(1): 201-208.

The multi-reflection X-ray method was used to determine the stress level in deformed and recrystallized polycrystalline copper samples. The anisotropic diffraction elastic constants were calculated using the self-consistent model and crystallographic texture. A significant decrease of the first order residual stresses was observed during recrystallization, but they start to decrease already during recovery. Diffraction peak widths and intensities were also examined. A complementary study, using synchrotron radiation and electron back scattering diffraction techniques, was done in order to determine the stored energy in the examined material. This latter is strongly orientation dependent and has the lowest value in the cubic orientation, which is dominating one in recrystalization texture.




104.    Wilkinson, A. J. (1991). "Deformation Studies of Metal Matrix Composites Using Electron Backscatter Patterns." Materials Science and Engineering A 135(MAR): 189-193.




105.    Wilkinson, A. J. (1996). "Measurement of elastic strains and small lattice rotations using electron back-scatter diffraction." Ultramicroscopy 62(4): 237-247.

A method is presented for the determination of elastic strains from electron back scatter diffraction patterns, which are obtained at high spatial resolution, from bulk specimens in a scanning electron microscope. It is estimated that the method is sensitive to strains of the order of 0.02%. Strains in Si1 minus xGex epitaxial layers grown on planar Si substrates were measured for x from 0.2 to 0.015, there being excellent agreement with X-ray diffraction results. Small lattice rotations can also be measured, the technique being sensitive to rotations of 0.01 degree, which offers an improvement of approximately two orders of magnitude from the more usual EBSD measurements of misorientation. Small lattice rotations were measured in Si0.85Ge0.15 grown on a patterned Si substrate and were consistent with elastic relaxation of the epilayer strain energy. (Author abstract) [References: 17]




106.    Wilkinson, A. J. (1997). "Methods for determining elastic strains from electron backscatter diffraction and electron channeling patterns." Materials Science and Technology 13(1): 79-84.

Since the mid-1980s, electron back-scatter diffraction (EBSD, also known as back-scatter Kikuchi diffraction, BKD) has become a well-known and often used technique for interrogating the local characteristics of microstructures. The more recent development of orientation imaging microscopy (OIM) has led to the practical application of EBSD in obtaining statistically relevant information from bulk materials. Many new developments in OIM technology have evolved recently. One of these is the development of rapid and more reliable mapping of multi-phase alloys. In addition, significant work has been performed on thin film structures including patterned films and integrated circuits for investigation of texture evolution, grain growth, and circuit reliability. An additional example showing the application of OIM on rough surface specimens, such as fracture surfaces, is discussed. (11 References).




107.    Wilkinson, A. J. (1997). "Probing Local Strain Fields Using Electron-Diffraction in the Scanning Electron-Microscope." Institute of Physics Conference Series(153): 221-226.




108.    Wilkinson, A. J. (1999). Measurement of Small Misorientations Using Electron Back Scatter Diffraction. Electron Microscopy and Analysis Group Conf., Sheffield, IOP Publishing Ltd.




109.    Wilkinson, A. J. (2000). "Advances in SEM-based diffraction studies of defects and strains in semiconductors." Journal of Electron Microscopy 49(2): 299-310.

Two scanning electron microscope (SEM)-based diffraction techniques, i.e. electron channelling contrast imaging (ECCI) and electron backscatter diffraction (EBSD) are used to study lattice defect and local elastic strain distributions in Si1-x/Gex epilayers grown on Si substrates patterned with mesas. The ECCI technique allows the misfit dislocations to be imaged in bulk samples. The misfit dislocations caused plastic relaxation of the strain in planar regions between mesas and in the wider mesas. In the narrower mesas the removal of lateral constraint at the mesa side faces had reduced the stress sufficiently to suppress the propagation of dislocations parallel to the closely spaced side faces. The measurements of small changes in the positions of two zone axes in EBSD patterns caused by variations in the local strain field were used to determine the strains and rotations making up the generalized plane strain tensor describing the deformation in the long mesa structures. The strain sensitivity of the method was determined to be ~±2x10-4. Distributions of strains and rotations across mesas of several dimensions are reported and differ significantly between mesa for which the mesa's width to epilayer thickness is high and low.




110.    Wilkinson, A. J. (2000). Measuring Strains Using Electron Backscatter Diffraction. Electron Backscatter Diffraction in Materials Science. A. J. Schwartz, M. Kumar and B. L. Adams. New York, Kluwer Academic/Plenum Publishers: 231-44.




111.    Wilkinson, A. J. (2001). "A new method for determining small misorientations from electron back-scatter diffraction patterns." Scripta Materialia 44(No. 10): 2379-2385.




112.    Wilkinson, A. J. and D. J. Dingley (1991). "Quantitative deformation studies using electron back scatter patterns." Acta Metallurgica et Materialia 39(12): 3047-3055.

The diffuseness of electron back scatter patterns (EBSPs) is observed to increase with plastic strain. The application of this technique to deformation studies has been limited by the lack of a general method of measuring the pattern quality. The degradation of EBSP's by cold work was thus thoroughly investigated using the Al 6061 alloy for the purpose. Methods for enhancing the Kikuchi band contrast by removal of the background intensity variation from digital images of left angle bracket 112 right angle bracket zone axes present in the EBSP have been developed. The constrast of the Kikuchi bands was quantified using the root mean square intensity of averaged band profiles, while the sharpness of the patterns was assessed by the attenuation of high frequency components of Fourier transforms of the enhanced images and of the averaged band profiles. Tilt was found to effect contrast but not sharpness, while cold work reduced both. However, surface contamination produced effects that were very similar to those of specimen deformation. A method is presented for quantitative determination of EBSP quality, which is independent of grain orientation and is based on the first moment of power spectra (the square of the Fourier transform) of features common to all patterns to be compared. (Author abstract) [References: 17]




113.    Wilkinson, A. J. and D. J. Dingley (1992). "The Distribution of Plastic-Deformation in a Metal Matrix Composite caused by Straining Transverse to the Fiber Direction." Acta Metallurgica et Materialia 40(12): 3357-3368.




114.    Wilkinson, A. J. and P. B. Hirsch (1997). "Electron diffraction based techniques in scanning electron microscopy of bulk materials." Micron 28(4): 279-308.

The three scanning electron microscope diffraction based techniques of electron channelling patterns (ECPs), electron channelling contrast imaging (ECCI), and electron backscatter diffraction (EBSD) are reviewed. The dynamical diffraction theory is used to describe the physics of electron channelling, and hence the contrast observed in ECPs (and EBSD) and ECCI images of dislocations. Models for calculating channelling contrast are described and their limitations discussed. The practicalities of the experimental methods, including detector- specimen configurations, spatial resolution and sensitivities are given. Examples are given of the use of ECCI for imaging and characterising lattice defects, both individually and in groups, in semiconductor heterostructures and fatigued metals. Applications of the EBSD technique to orientation determination, phase identification and strain measurement are given and compared with use of ECPs. It is concluded that these techniques make the SEM a powerful instrument for characterising the local crystallography of bulk materials at the mesoscopic scale.




115.    Wilkinson, A. J., D. J. Dingley, et al. (1993). "The Measurement of Local Plastic Deformation in Metal Matrix Composite by EBSP." Journal of Microscopy 169: 255-261.





116.    Wilkinson, A. J., G. Meaden, et al. (2006). "High-resolution elastic strain measurement from electron backscatter diffraction patterns: New levels of sensitivity." Ultramicroscopy 106(4-5): 307-313.

In this paper, we demonstrate that the shift between similar features in two electron backscatter diffraction (EBSD) patterns can be measured using cross-correlation based methods to ±0.05 pixels. For a scintillator screen positioned to capture the usual large solid angle employed in EBSD orientation mapping this shift corresponds to only 8.5×10−5 rad at the pattern centre. For wide-angled EBSD patterns, the variation in the entire strain and rotation tensor can be determined from single patterns. Repeated measurements of small rotations applied to a single-crystal sample, determined using the shifts at four widely separated parts of the EBSD patterns, showed a standard deviation of 1.3×10−4 averaged over components of the displacement gradient tensor. Variations in strains and rotations were measured across the interface in a cross-sectioned Si1−xGex epilayer on a Si substrate. Expansion of the epilayer close to the section surface is accommodated by tensile strains and lattice curvature that extend a considerable distance into the substrate. Smaller and more localised shear strains are observed close to the substrate–layer interface. EBSD provides an impressive and unique combination of high strain sensitivity, high spatial resolution and ease of use.




117.    Williams, D. B. and D. E. Newbury (1984). "Recent Advances in Electron-Microscopy of Materials." Advances in Electronics and Electron Physics 62: 161-288.




118.    Williams, G. O., V. Randle, et al. (2004). "The role of misorientation and phosphorus content on grain growth and intergranular fracture in iron-carbon-phosphorus alloys." Journal of Microscopy 213(Pt 3): 321-327.

The relationship between the crystallography of intergranular fracture and phosphorus segregation has been investigated in a Fe-0.06wt%P-0.002wt%C alloy aged for 1 h at temperatures between 600 degrees C and 1000 degrees C. Two novel techniques were devised for the investigation: first, electron back-scatter diffraction (EBSD) across the reconstructed fracture surface and, second, a combination of Auger electron spectroscopy, stereophotogrammetry and microscopy to measure phosphorus and carbon on fracture facets combined with EBSD measurements direct from the fracture surface. In total, 700 misorientations were measured from across the reconstructed fracture surface and in 'control' areas away from the fracture. It was found that Sigma 3s were in general more resistant to brittle fracture than were random boundaries, and it was suggested that alloys of this type could be grain boundary engineered to improve fracture resistance by a short anneal in the austenite region to increase the final proportion of Sigma 3s. Sixteen fracture facets yielded combined Auger/EBSD data. The combined Auger/EBSD methodology to acquire joint crystallographic and segregation information from facets was shown to be feasible, although laborious. There were significantly more 110 planes than any other type in the sample population of facets from which combined segregation/crystallography data had been collected. The data suggested that there was on average lower phosphorus segregation on fracture facets that were near 110 than on other intergranular fracture facets.




119.    Wilson, A. W. and G. Spanos (2001). "Application of orientation imaging microscopy to study phase transformation in steels." Materials Characterization 46(5): 407-18.

In this investigation, the methodology, advantages, and limitations of using Orientation Imaging Microscopy (OIM) to study microstructures in multiphase steels are examined. In particular, proeutectoid ferrite precipitation has been investigated in a hypoeutectoid steel (Fe–0.12%C–3%Ni), while the proeutectoid cementite transformation has been studied in a hypereutectoid steel (Fe–1.3%C–13%Mn). By utilizing misorientation maps and inverse pole figure maps to determine the orientation differences between individual crystals, the internal morphology of the solid-state precipitates has been determined. What appear by other types of imaging to be monolithic single crystals are shown to be aggregates of finer crystals with misorientations between them. The relative quality of the Electron Backscatter Diffraction (EBSD) patterns has been correlated to specific phases and to interphase and grain boundaries using pattern quality maps (also referred to as image quality maps). These techniques have been adapted for quantitative identification of different microconstituents, including volume fraction measurements. By making comparisons among optical micrographs, conventional SEM micrographs, pattern quality maps, inverse pole figure maps, and misorientation maps, the advantages and limitations of different types of OIM mapping for studying different aspects of phase transformations in steels are elucidated.




120.    Wilson, A. W., J. D. Madison, et al. (2001). "Determining phase volume fraction in steels by electron backscattered diffraction." Scripta Materialia 45(12): 1335-1340.

The relative sharpness of electron backscattered diffraction (EBSD) patterns is used to quantify the volume fraction of ferrite in low-carbon steels. EBSD pattern quality (PQ) maps are shown to improve imaging of martensite and ferrite over optical and secondary electron imaging. Ferrite volume fraction in isothermally reacted Fe-0.12C-3.28Ni are quantified using PQ maps by manual point counting and image thresholding.




121.    Winning, M. and S. Badirujjaman (2004). "Mobility of grain boundaries in stress fields." Materialprufung 46(3): 92-95.

The mobility of grain boundaries under certain conditions is a key factor for the evolution of polycrystalline microstructures and material properties. In recent experiments it was shown that grain boundaries can interact with mechanical stress fields and that the motion of planar grain boundaries, low angle as well as high angle grain boundaries, could be induced by an external mechanical stress field. Therefore the current study was performed to investigate the details of grain boundary motion and interactions between definite, planar grain boundaries and the mechanical stress field during high temperature low cycle deformation of high purity aluminium bicrystals. The grain boundary planes were in all cases perpendicular to the loading axis. Experiments were made with large as well as small stresses at different temperatures and numbers of cycles. The displacement of grain boundaries was measured by using optical microscopy, and the microstructural features, as well as orientations of individual grains were recorded by the electron backscatter diffraction technique (EBSD) after each deformation experiment.




122.    Winther, G., X. Huang, et al. (2004). "Critical comparison of dislocation boundary alignment studied by TEM and EBSD: technical issues and theoretical consequences." Acta Materialia 52(15): 4437-4446.

The plane of extended deformation induced boundaries (geometrically necessary boundaries) determined by transmission electron microscopy (TEM) has previously been found to be grain orientation dependent so that some grains have boundaries aligned with slip planes while others do not. However, in both types of grains the boundaries are aligned with macroscopic planes. A recently published analysis by electron backscattered diffraction (EBSD) found no evidence for alignment of boundaries with slip planes or any other simple crystallographic plane, i.e. only macroscopic alignment. This discrepancy is discussed based on a critical comparison of the TEM and EBSD based techniques and TEM observations of boundary planes in grains of selected orientations in cold-rolled aluminium. The latter clearly show that the EBSD finding is incorrect. The present analysis thereby confirms that grain orientation-dependent boundary planes is a general phenomenon.




123.    Wołczynski, W. and M. Faryna (2003). "Correlation between solute redistribution and crystal orientation in Fe–4.34 wt.% Ni alloy directionally solidified by the Bridgman technique." Materials Chemistry and Physics 81: 513-517.

A cellular structure has been produced in a directionally solidified Fe–4.34 wt.% Ni alloy. Double instability at the cell tip was revealed and described as a first harmonic wave of the fundamental undulation. The Ni solute redistribution was measured just above the bottom of the tip splitting. An increase of the solute content corresponds well to the location of the tip splitting. The presence of ferrite (δ) and initiation of (d)/austenite (γ) transformation have been confirmed by the use of automatic crystal orientation mapping. A continuous disappearance of the subgrain structure with decreasing temperature and increasing contribution of d/g transformation was observed.




124.    Woldt, E. and D. J. Jensen (1995). "Recrystallization Kinetics in Copper - Comparison Between Techniques." Metallurgical and Materials Transactions A 26(7): 1717-1724.

Six different experimental techniques (electron backscattering (Kikuchi) patterns, calorimetry, micro and macrohardness, orientation contrast scanning electron microscopy, and neutron diffraction) have been used to determine the volume fraction of recrystallized material X(t)in a series of partly recrystallized copper samples. Before recrystallization, the copper samples were cold-rolled to 92 pct reduction thickness. The results obtained with the different experimental techniques are compared, and the applicability and accuracy of the six techniques are considered. While five of the techniques reveal the same kinetics, although with different degrees of accuracy, the texture measurements by neutron diffraction seem to indicate a faster recrystallization process. Finally, the recrystallization kinetics and stored energy aspects of the copper material are discussed with respect to the Johnson-Mehl-Avrami-Kolmogorov model.




125.    Wollmer, S., S. Zaefferer, et al. (2003). "Characterization of phases of aluminized nickel base superalloys." Surface and Coatings Technology 167: 83-96.

Aluminum rich coatings, built up by a diffusion zone and a NiAl-cover layer, can protect the surface of turbine blades against oxidation. Within the single crystalline substrate and the adjacent layer, phases in the range of several tens of nanometers up to a few micrometers develop during production and operation of the turbine blade, were characterized. Investigations with transmission electron microscopy, nanoindentation and local crystal orientation mapping with a scanning electron microscope have been carried out in order to determine composition, morphology and distribution of the different phases. The diffusion zone has in general a defined orientation relative to the superalloy substrate and is built up by at least three phases embedded in a softer matrix, with significant differences in nanohardness. Local internal stress states in the diffusion zone are estimated. The NiAl-cover layer is a coarse columnar grained, non-textured B2 ordered intermetallic NiAl-phase.




126.    Woodcock, T. G., J. S. Abell, et al. (2002). "Characterisation of textured NiO films for application as buffer layers in high temperature superconducting tapes." Journal of Microscopy 205(3): 231-237.

Textured NiO films have been grown, by thermal oxidation, on biaxially textured Ni substrates. The films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The XRD results showed two texture components, cube texture (001)[100] and (111) with out of plane orientation only. SEM showed much inhomogeneity of grain size on the sample surface. Analysis by EBSD revealed that coarse grained regions were cube textured and fine grained regions were <111> fibre textured. The ability to correlate textural and microstructural data is crucial to the optimization of textured NiO films for use in coated conductor technology.




127.    Woodcock, T. G., J. S. Abell, et al. (2002). "The effect of different oxidation routines on the properties of surface oxidised epitaxial NiO layers on biaxially textured Ni tapes." Physica C 372-376: 863-865.

Surface oxidation epitaxy layers were produced by thermal oxidation of biaxially textured Ni tape under two different regimes. Firstly, upquenching to the oxidation temperature (1200°C) and down quenching after holding for 1 h and secondly, ramping up at 300°C/h and furnace cooling after holding. The texture and morphology of the oxide layers obtained were assessed by X-ray diffraction and electron backscatter diffraction. Both samples exhibited a 45° rotated cube texture associated with smooth regions on the oxide surface and a <111> fibre texture associated with protruding, rough regions. The ramped sample had a much lower density of these rough regions and is therefore more suitable for the deposition of subsequent, functional layers.




128.    Woodcock, T. G., J. S. Abell, et al. (2004). "Crystal orientation mapping of NiO grown on cube textured Ni tapes." Journal of Microscopy 216(Pt. 2): 123-130.

Samples of cube textured Ni tapes were oxidized in flowing oxygen at different temperatures. Crystal orientation maps (COMs) of the resulting oxide layers were produced by electron backscatter diffraction. The oxide layers were also analysed by X-ray diffraction (XRD), scanning electron microscopy and atomic force microscopy (AFM). The oxide grain size of a sample oxidized at 600 ° C was similar to that of the substrate and the oxide was highly textured, both indicating epitaxial growth. The orientation relationship between the substrate and the oxide was directly observed from XRD to be (111) NiO (001) Ni, [1 01] NiO [110] Ni with four, equivalent, in-plane variants. In each variant, the oxide has both <110>- and <211>-type directions parallel to the Ni <110> directions. Differences in oxide thickness and surface roughness on neighbouring grains were revealed by AFM and these were attributed to the existence of a range of oxide growth conditions resulting from small differences in the orientation of each substrate grain. Similar macrotexture and microstructure were observed on a sample oxidized at 1300 ° C, but additional, facetted oxide crystals had formed at the oxide grain boundaries. COMs showed that these crystals were either cube or 45 ° rotated cube orientated, a texture different to that of the large oxide grains. The grain boundary crystals were thought to form by inward diffusion of oxygen at defects in the growing oxide scale.




129.    Woodfield, A. P. and J. A. Sutliff (1997). "The Influence of Microtexture on Fatigue Behavior of Titanium Alloys." Microscopy and Microanalysis 3(2): 571-572.




130.    Wouters, O., W. P. Vellinga, et al. (2005). "On the evolution of surface roughness during deformation of polycrystalline aluminum alloys." Acta Materialia 53: 4043-4050.

Surface roughening of polycrystalline Al–Mg alloys during tensile deformation is investigated using white light confocal microscopy. Materials are tested that differ only in grain size. A height–height correlation technique is used to analyze the data. The surface obeys self-affine scaling on length scales up to a correlation length which approximately equals the grain size and above which no height correlation is present. The self-affine scaling exponent increases initially with strain and saturates at a value around 0.9. A linear relation is observed between root-mean-square roughness and both strain and grain size. The observed roughness is explained as the result of the combined effect of a self-affine roughening on a subgrain scale and a grain scale roughening caused by orientation differences between neighboring grains.




131.    Wouters, O., W. P. Vellinga, et al. (2006). "Effects of crystal structure and grain orientation on the roughness of deformed polycrystalline metals." Acta Materialia 54(10): 2813-2821.

Surface roughening during tensile deformation of polycrystalline aluminum, iron and zinc is investigated using white light confocal microscopy and orientation imaging microscopy. A height–height correlation technique is used to analyze the data. The surface obeys self-affine scaling on length scales up to a correlation length which approximately equals the grain size and above which no height correlation is present. The self-affine scaling exponent increases initially with strain and saturates at a value around 0.9 for aluminum and at 0.8 for iron and zinc. A linear relation is observed between root mean square roughness and strain. The observed grain scale roughening is explained as arising from orientation differences between neighboring grains and depends on the available number of slip systems in the material. Orientation imaging microscopy is used to investigate the influence of the orientation of the surface grains and subsurface grains on the topography. It is found that the Schmid factor of surface grains alone is not enough to predict local deformation and evolution of surface height. In particular, grains with high Schmid factor may show less deformation than expected. It is shown that subsurface grains influence the roughness and it is hypothesized that a high cumulative Schmid factor on a cross-section below a point at the surface leads to a depression at the surface.




132.    Wright, S. I. (1992). Individual Lattice Orientation Measurements Development and Applications of a Fully Automatic Technique. Mechanical Engineering. New Haven, Yale: 214.




133.    Wright, S. I. (1993). "Review of automated orientation imaging microscopy (OIM)." Journal of Computer Assisted Microscopy 5: 207-221.

This review describes a new experimental technique for investigating the spatial arrangement of crystallographic orientation in polycrystalline materials. Several methods for measuring lattice orientations on an individual point basis are briefly described. A completely automated system for making spatially specific orientation measurements based on automatic analysis of electron backscatter Kikuchi diffraction patterns is described in detail. The system couples precise movement of a computer controlled stage in the scanning electron microscope with automatic analysis of diffraction patterns to achieve rapid measurement of lattice orientations at prescribed points in the polycrystalline microstructure. Several examples of images formed from data obtained using this system are presented. A sampling of statistical analyses for interrogating the data are also given. (Author abstract) [References: 0]




134.    Wright, S. I. (1994). Automatic indexing of electron-backscatter diffraction patterns. Fifty-Second Annual Meeting Microscopy Society of America/Twenty-Ninth Annual Meeting Microbeam Analysis Society, New Orleans, LA, San Fancisco Press, Inc.

A typical Backscatter Kikuchi Diffraction (BKD) pattern is presented. Since the bands in the pattern represent planes in the diffracting volume, the lattice orientation can be determined from their geometrical arrangement. Recent advances in feature detection in BKDs along with methods for digital image enhancement were described in detail. The determination of orientation from a set of detected bands was also discussed. [References: 11]




135.    Wright, S. I. (1994). "Estimation of Single Crystal Elastic Constants from Textured Polycrystal Measurements." Journal of Applied Crystallography 27: 794-801.




136.    Wright, S. I. (1999). Quantification of Recrystallized Fraction from Orientation Imaging Scans. The Twelfth International Conference on Textures of Materials (ICOTOM 12), Ottawa, NRC Research Press.

Two methods have been proposed for distinguishing recrystallized structure from deformed structure in a polycrystalline material using electron backscatter diffraction (EBSD) in the scanning electron microscope. One based on the quality of the diffraction images and another based on misorientations. With the wide acceptance of automation orientation measurement techniques based on EBSD, a method is needed for differentiating recrystallized and deformed material based on the data obtained from these automatic techniques. Adaptation of the proposed methods for distinguishing recrystallized and deformed into the framework of the automated orientation measurement techniques is presented. Results obtained from the orientation scanning technique are compared to results obtained using conventional metallography in partially recrystallized low carbon steel. Differences between the proposed method and the conventional technique are discussed and the influence of various parameters on these differences analyzed.




137.    Wright, S. I. (2000). Fundamentals of Automated EBSD. Electron Backscatter Diffraction in Materials Science. A. J. Schwartz, M. Kumar and B. L. Adams. New York, Kluwer Academic/Plenum Publishers: 51-61.




138.    Wright, S. I. (2002). "Investigation of Coincident Site Lattice (CSL) Boundary Criteria in Cu Thin Films." Journal of Electronic Materials 31(1): 50-54.

A statistical investigation of the coincident site lattice (CSL) sigma=3 boundaries was performed on a Cu thin film sample. The criteria used to judge whether a given boundary is a CSL bundary were evaluated. The misorientation criterion, i.e., how near a given boundary misorientation must lie to an ideal CSL misorientation, was addressed. The results showed that the amount of allowed deviation has little impact on the CSL distribution (within the range of published values for the deviation tolerance). The second criterion addressed was the alignment of the boundary planes with coherent planes in the adjoining grains. Because the measurements were made on single section planes, the orientation of a boundary plane could not be fully measured. Rather, only the orientation of the trace of a boundary plane could be measured. The deviation of the alignment of the boundary traces and the corresponding coherent plane traces were measured. The measurements showed that the choice of a tolerance for the allowed trace deviation was significant.




139.    Wright, S. I. and B. L. Adams (1990). Automated Lattice Orientation Determination from Electron Backscatter Kikuchi Diffraction Patterns. Ninth International Conference on Textures of Materials (ICOTOM 9), Avignon, France, Gordon and Breach Science Publishers.




140.    Wright, S. I. and B. L. Adams (1990). "An Evaluation of the Single Orientation Method for Texture Determination in Materials of Moderate Texture Strength." Textures and Microstructures 12: 65-76.




141.    Wright, S. I. and B. L. Adams (1992). "Automatic-analysis of electron backscatter diffraction patterns." Metallurgical Transactions A 23(3): 759-767.

The review describes the use of an experimental technique known as electron backscatter diffraction (EBSD) to measure microtexture, that is, spatially specific texture measured on an individual orientation basis. Other methods of microtexture determination are briefly described and compared with EBSD. The EBSD technique itself is described in considerable detail including recent developments such as online automation. Those EBSD-based microtexture studies which have been reported in the literature are summarized, including those which provide a direct comparison with macrotexture measurements obtained by X-ray diffraction. The concept of microtexture as the texture of individual grains leads naturally to the idea of 'mesotexture' as the texture of grain boundaries. Mesotexture data can be computed from the EBSD-generated microtexture measurements and this is demonstrated and examples are given. Examples of microtexture/mesotexture studies in multiphase materials are also shown. The review is completed by a discussion of the representation of microtextures and mesotextures, including the use of Rodrigues-Frank space and orientation mapping. (106 References).




142.    Wright, S. I. and D. J. Dingley (1998). Orientation Imaging in the Transmission Electron Microscope. Twelfth International Conference on Texture and Anisotropy of Polycrystals in Materials Science Forum, Zurich, Trans Tech.




143.    Wright, S. I. and D. P. Field (1997). Analysis of Multiphase Materials Using Electron Backscatter Diffraction. Microscopy and Microanalysis 1997, Cleveland, Ohio, Springer.




144.    Wright, S. I. and D. P. Field (1998). "Recent studies of local texture and its influence on failure." Materials Science and Engineering A 257(1): 165-170.

Advances in techniques for measuring individual crystallographic orientations in polycrystals have made it possible to investigate the role of local crystallography on failure in polycrystalline materials in more detail than previously possible. In particular, the automated electron backscatter diffraction technique is particularly well suited for making spatially specific measurements of crystallographic orientation. This tool has made it practical to characterize the local distribution of orientations in polycrystalline microstructures with statistical significance. This work reviews the application of the automatic electron backscatter diffraction technique to the characterization of the various crystallographic parameters associated with failure. Several approaches for investigating the role of various crystallographic parameters on crack behavior in polycrystals are shown in the context of statistical distribution functions along with the use of the automated electron diffraction technique for acquiring the necessary orientation data.




145.    Wright, S. I. and D. P. Field (2005). Scalar Measures of Texture Heterogeneity. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

Since electron backscatter diffraction (EBSD) provides spatially specific measurements of crystallographic orientation, automated EBSD or Orientation Imaging Microscopy (OIM) is well suited to the characterization of local variations in texture as well as larger gradients in texture. Texture heterogeneities are often apparent in maps generated by mapping various orientation parameters on to a color scale. While orientation maps provide a qualitative indication of the presence of spatial texture variations, a quantitative description is needed. Some parameters have been proposed [1] for quantifying texture gradients and texture banding. However, the calculation of these parameters is very sensitive to various measurement parameters such as the step size between points in the scan relative to the observed texture variations. Improvements to the existing calculation methodology are reported. A new approach is also presented and results compared with the previously reported methodology.




146.    Wright, S. I. and F. Heidelbach (1994). "Microtextural Characterization of Annealed and Deformed Copper." Materials Science Forum 157-162: 1313-1318.

Grain boundary textures of copper in two different states are examined using backscatter electron Kikuchi diffraction patterns (BEKPs) in the scanning electron microscope. Local orientation relationships across a former recrystallization twin boundary after deformation are explored in detail using automated BEKP analysis. The misorientation distribution of the annealed sample is dominated by twin relationships (primary and secondary). The deformed sample has a misorientation distribution close to random and the twin relationships are lost. The twin boundary is transformed into a "normal" boundary




147.    Wright, S. I. and G. T. Gray III (1994). Characterization of a Texture Gradient in Tantalum Plate. Third International Symposium on Structural and Functional Gradient Materials, Lausanne, Switzerland, Presses Polytechniques et Universitaires Romandes.

Clark et al. have shown that significant texture gradients can be produced in rolled tantalum plate and that the strength of the gradient is dependent on the processing path. Texture gradients are often ignored because they are time consuming to characterize and add significant complexity to materials modeling. The variation in texture through the thickness of rolled materials is most commonly measured by sectioning samples to different depths through the thickness of the plate and then measuring the texture from these section planes by X-ray diffraction. A new technique based on automatic indexing of electron backscatter diffraction patterns in the scanning electron microscope enables spatially specific orientations to be measured in a practical manner. This technique allows spatial variations in texture to be measured directly enabling gradients in texture to be investigated in more detail than previously possible. This data can be used directly in coupled finite-element/polycrystal-plasticity models to simulate the effects of variations in texture on the plastic behavior of polycrystals. This work examines the variation in texture through the thickness of a tantalum plate and its resultant effect on the compressive deformation of samples prepared from the plate. The characterization of the texture gradient using the automatic point-by-point measurement technique mentioned above is described in detail. The effect of the gradient on the plastic response of through-thickness compression tests is also discussed.




148.    Wright, S. I. and J. D. Cotton (1995). "Microtextural Characterization of a Beryllium Weldment." Textures and Microstructures 23: 7-19.




149.    Wright, S. I. and J. F. Bingert (1995). Fractures, Fractals and Local Orientation Relationships. Los Alamos, Los Alamos National Laboratory.




150.    Wright, S. I. and M. M. Nowell (2002). Chemistry Assisted Phase Differentiation in Automated Electron Backscatter Diffraction. Microscopy and Microanalysis 2002, Québec City, Québec, Canada, Cambridge University Press.




151.    Wright, S. I. and M. M. Nowell (2002). EDS Assisted Phase Differentiation in Orientation Imaging Microscopy. Materials Research Congress, Cancun, Mexico.

Automated Electron Backscatter Diffraction (EBSD) or Orientation Imaging Microscopy (OIM) has been proven to be a viable technique for investigating microtexture in polycrystalline materials. It is particularly useful for investigating orientation relationships between phases in multiphase materials. However, when phases do not significantly vary in crystallographic structure, OIM is limited in its capability to reliably differentiate between phases. Through simultaneous collection of EBSD data and chemical data via X-Ray Energy Dispersive Spectroscopy (EDS), it is possible to dramatically improve upon the phase differentiation capabilities of either technique individually. This presentation will introduce a methodology for combining the two techniques, as well as show a few example applications.




152.    Wright, S. I. and M. M. Nowell (2004). Improvements in the Characterization of Multiphase Materials by Automated Electron Backscatter Diffraction. Proceedings of the 8th Asia-Pacific Conference on Electron Microscopy (8APEM). N. Tanaka, Y. Takano, H. Moriet al. Ishikawa, Japan, 8APEM Publication Committee: 264-265.

EBSD is well suited for characterizing orientation relationships between phases in polycrystals. For accurate results, it is important to reliably differentiate between patterns from the constituent phases during the automated scanning process. When phases have similar crystal structure but dissimilar chemical composition, the reliability of the phase differentiation process can be dramatically improved by incorporating simultaneously collected chemical information via XEDS. In the converse situation, where the compositions are similar and the structures dissimilar, there may be patterns from specific orientations that cannot be reliably identified. Using simulated patterns, suspect orientations can be identified and conditions optimized for improved reliability.




153.    Wright, S. I. and M. M. Nowell (2005). "A review of in-situ EBSD experiments." Chinese Journal of Stereology and Image Analysis 10(4): 193-198.

Automated EBSD or Orientation Imaging Microscopy (OIM) systems are being used in combination with other equipment within the scanning electron microscope (SEM) to perform in-situ measurements. This paper briefly reviews OIM studies of in-situ experiments performed using tensile and heating stages as well as in-situ serial sectioning. In particular, in-situ OIM scan results on an aluminum alloy sample deformed in tension; phase transformations in a cobalt sample, recrystallization and grain growth in a copper sample and serial sectioning of a nickel super-alloy sample are reviewed.




154.    Wright, S. I. and M. M. Nowell (2006). "EBSD Image Quality Mapping." Microscopy and Microanalysis 12: 72-84.

Image quality (IQ) maps constructed from electron backscatter diffraction data provide useful visualizations of microstructure. The contrast in these maps arises from a variety of sources, including phase, strain, topography, and grain boundaries. IQ maps constructed using various IQ metrics are compared to identify the most prominent contrast mechanism for each metric. The conventional IQ metric was found to provide the superior grain boundary and strain contrast, whereas an IQ metric based on the average overall intensity of the diffraction patterns was found to provide better topological and phase contrast.




155.    Wright, S. I. and R. J. Larsen (2002). "Extracting Twins from Orientation Imaging Microscopy Scan Data." Journal of Microscopy 205(3): 245-252.

Automated electron backscatter diffraction or orientation imaging microscopy (OIM) provides spatially specific measurements of crystallographic orientation. These measurements are typically collected on regular grids. By inspecting the misorientation between neighbouring measurements on the grid, potential twin boundaries can be identified. If the misorientation is within some given tolerance of a specified twin misorientation, the boundary separating the two measurements may be identified as a potential twin boundary. In addition, for a coherent twin, the twinning planes must be coincident with the grain boundary plane. As OIM scans are inherently two-dimensional, the scan data provide only limited information on the boundary plane. Thus, it is not possible to ascertain definitively whether the twinning planes are coincident with the boundary plane. Nonetheless, the alignment of the surface traces of the twinning planes with the trace of the boundary provides a partial indication of coincidence. An automated approach has been developed that allows data concerning both twin criterion to be extracted from OIM scans. Application of the methodology to deformed zirconium suggests that the twinning planes remain coherent during deformation. The methodology was also used to improve grain size distributions measured by OIM. These results more closely match those obtained by conventional metallography.




156.    Wright, S. I. and U. F. Kocks (1996). A Comparison of Different Texture Analysis Techniques. Eleventh International Conference on Textures of Materials, Xi'an, China, International Academic Publishers.




157.    Wright, S. I. and W. J. Poole (1996). Local Textures in Metal Matrix Composites. Processing, Properties and Applications of Cast Metal Matrix Composites, Cincinnati, Ohio, TMS.

The local distribution of preferred orientation and misorientation in a model composite system is investigated using electron diffraction in the scanning electron microscope. These preliminary results demonstrate the utility of new automated techniques for characterizing local textures using electron diffraction in composite materials. The composite investigated was comprised of tungsten fibers in a polycrystalline copper matrix. The local textures of samples before and after the deformation were measured. The results show an increase in local texture near the reinforcing fibers after deformation. The misorientation distributions showed a breakdown of the twin boundaries in the deformed material relative to the starting material and an increase in small angle misorientations.




158.    Wright, S. I., A. J. Beaudoin, et al. (1994). "Texture Gradient Effects in Tantalum." Materials Science Forum 157-162: 1695-1799.




159.    Wright, S. I., B. L. Adams, et al. (1991). "Automated determination of lattice orientation from electron backscattered Kikuchi diffraction patterns." Textures and Microstructures 13: 2-3.

As described in a previous paper (see ibid., vol.12, p.65-76 1990), with the advent of new techniques it has become practical to consider using single orientation measurements for texture investigations. Advantages of using single orientation measurements over the traditional bulk measurement using pole figures are: direct access to odd-l terms in the series expansion of the orientation distribution function (ODF) (1982) and the capability to measure local textures and to obtain spatial orientation correlation information. The primary obstacle to the use of single orientation measurements is the large investment of direct operator time required to obtain a statistically reliable data set. this study examines a technique that has been developed to automate the orientation identification process. The technique essentially compares an electron backscattered Kikuchi diffraction (BKD) pattern with a set of idealized patterns and finds the best match. The set of idealized patterns is created from a set of orientations which represent a tessellation of the asymmetric region of Euler space. The technique shows promising preliminary results, BKD patterns for silicon and stainless steel were correctly identified by the computer. (7 References).




160.    Wright, S. I., B. L. Adams, et al. (1993). "Application of New Automatic Lattice Orientation Measurement Technique to Polycrystalline Aluminum." Materials Science and Engineering A 160(2): 229-240.




161.    Wright, S. I., D. J. Dingley, et al. (1996). Determining Deformation, Recovery and Recrystallization Fractions from Orientation Imaging Microscopy (OIM) Data. Microscopy and Microanalysis, Minneapolis, San Francisco Press.

While orientaiton imaging microscopy (OIM) via automatic analysis of electron backscatter diffraction patterns (EBSP's) has become routine, methods for analyzing results obtained by OIM are still maturing. Interrogating the OIM data to distinguish between deformed, recovered and recrystallized material in a polycrystalline sample is one example. An advantage for using OIM data in such a case is that the corresponding textures can also be determined providing more information regarding these processes. This work reports on two different approaches for distinguishing between these structures from OIM data on a sample of partially recrystallized low-alloy steel.




162.    Wright, S. I., D. P. Field, et al. (2000). Advanced Software Capabilities for Automated EBSD. Electron Backscatter Diffraction in Materials Science. A. J. Schwartz, M. Kumar and B. L. Adams. New York, Kluwer Academic/Plenum Publishers: 141-52.




163.    Wright, S. I., D. P. Field, et al. (2002). On the Development of New Scalar Measures of Heterogeneity. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

One of the key advantages of measuring textures by electron backscatter diffraction (EBSD) is the ability to obtain spatially specific orientation data. This allows the spatial distribution of texture or microtexture to be characterized. The local variation in texture is often apparent in maps generated by mapping various orientation parameters on to a color scale. While orientation maps provide a visual indicator of local texture variations, a quantitative description is needed for compasring the heterogeneity between different materials. This paper reports on two scalar parameters developed for characterizing heterogeneity - one parameter for characterizing the severity of texture gradients and the other for quantifying the degree of texture banding. The practical application of these measures to a tantalum sample is presented. Variations in the values measured for different scan densities were observed. Thus, a procedural resolution to mitigate these variations arising from the scanning conditions is proposed.




164.    Wright, S. I., D. P. Field, et al. (2003). The Applicability of Conventional Fiber Texture Analysis Techniques in Electron Backscatter Diffraction. Thermec' 2003, Leganés, Madrid, Spain, Trans Tech Publications Ltd.

Textures in thin films often exhibit fiber textures. A set of analyses has been developed for quantitative characterization of fiber textures using X-ray diffraction. These analyses techniques are generally based on rocking curve analysis or the reduction of pole figures into pole plots. The height and width of these plots are analyzed and characteristic measures such as peak and random fractions are extracted. These analysis techniques can be duplicated for texture measurements obtained by electron backscatter diffraction (EBSD) in the scanning electron microscope (SEM). However, differences have been observed in results obtained by EBSD and X-ray diffraction. The causes of these differences are examined. In light of these comparisons, a methodology for implementing the conventional fiber texture analysis techniques for EBSD data are proposed.




165.    Wright, S. I., D. P. Field, et al. (2005). Impact of Local Texture on Recrystallization and Grain

Growth via In-Situ EBSD. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

While electron backscatter diffraction (EBSD) has become an established technique within materials characterization labs around the world, the technique is still relatively young and new applications are continuing to emerge. Automated EBSD or Orientation Imaging Microscopy (OIM) systems are being used in combination with other equipment within the scanning electron microscope (SEM) to perform in-situ measurements. This includes tensile stages for observing changes in local orientation during deformation and heating stages for studying orientation changes arising during recrystallization and grain growth as well as phase transformations. In addition to these temporally three- dimensional studies, spatially three-dimensional studies can be performed by in-situ serial sectioning in microscopes equipped with both electron and focused ion beams. These in-situ techniques are briefly reviewed. The review is followed by a detailed analysis of in-situ heating experiments on copper. The movement of grain boundaries during recrystallization and subsequent grain growth are tracked. The effect of orientation relationships on grain boundary mobility and nucleation are explored. No special relationship with grain boundary mobility was observed. However, twins appear to play a significant role in the nucleation process.




166.    Wright, S. I., G. T. Gray III, et al. (1994). "Textural and Microstructural Gradient Effects on the Mechanical Behavior of a Tantalum Plate." Metallurgical and Materials Transactions A 25: 1025-1031.




167.    Wright, S. I., J. Bingert, et al. (2002). Advanced Characterization of Twins Using Automated Electron Backscatter Diffraction. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

This paper describes results obtained using an automated, crystallography-based technique for twin identification. The technique is based on the automated collection of spatially specific orientation measurements by electron backscatter diffracrion (EBSD) in the scanning electron microscope (SEM). The key features of the analysis are identification of potential twin boundaries by their misorientation character, identification of the distinct boundary planes among the symmetrically equivalent candidates, and validation of these boundaries through comparison with the boundary and twin plane traces in the sample cross section. Results on the application of this technique to deformation twins in zirconium are analyzed for the effect of twin type and amount and sense of uniaxial deformation. The accumulation of strain tends to increase the misorientation deviation at least to the degree of the trace deviation compared with recrystallization twins in nickel. In addition to the results on characterizing the twin character, results on extending the twin analysis to automated identification of parent and daughter material for structures exhibiting twin deformation are reported as well.




168.    Wright, S. I., J. F. Bingert, et al. (1996). "Microtextural zones in a copper shaped charge particle." Materials Science and Engineering A207: 224-227.




169.    Wright, S. I., J. F. Bingert, et al. (1996). "Microstructural Development in a Copper Shaped-Charge Fragment." Materials Science and Engineering 207: 224-7.




170.    Wright, S. I., J. F. Bingert, et al. (1996). Microtextural Characterization of Copper Shaped Charge Jet Fragments. Shock Compression of Condensed Matter-1995, American Institute of Physics: 1237-1240.




171.    Wright, S. I., M. M. Nowell, et al. (2004). Chemical prefiltering for phase differentiation via simultaneous energy dispersive spectrometry and electron backscatter diffraction. USA, Ametek/EDAX/TSL, Draper, Utah, USA: 11.

An analytical method for combining chemical information with crystallographic information to obtain a map of the crystal orientation, the nature of grain boundaries, and distinguishing crystalline phases in a polycrystalline sample, including the steps of providing a sample with a prescribed grid of points thereon, selecting a point, applying a collimated electron beam to the point to obtain an electron backscatter diffraction (EBSD) pattern and the elemental composition of the sample at the point. Recording the information and repeating for each point in the grid and determining the crystalline phases in the sample. An instrument capable of performing the method includes an SEM having means for applying an electron beam to a sample, means for obtaining an EBSD pattern (EBSP), and means for determining the composition of the sample, as well as means for recording EBSD band locations and characteristics and the elemental composition of the sample.




172.    Wu, C. T., B. L. Adams, et al. (2002). "Mapping the mesoscale interface structure in polycrystalline materials." Ultramicroscopy 93: 99-109.

A new experimental approach to the quantitative characterization of polycrystalline microstructure by scanning electron microscopy is described. Combining automated electron backscattering diffraction with conventional scanning contrast imaging and with calibrated serial sectioning,the new method (mesoscale interface mapping system) recovers precision estimates of the 3D idealized aggregate function GðxÞ: This function embodies a description of lattice phase and orientation (limiting resolution B11) at each point x (limiting spatial resolutionB100 nm),and,therefore, contains a complete mesoscale description of the interfacial network. The principal challenges of the method, achieving precise spatial registry between adjacent images and adequate distortion correction,are described. A description algorithm for control of the various components of the system is also provided.




173.    Wu, G. and D. J. Jensen (2005). "Recrystallisation kinetics of aluminium AA1200 cold rolled to true strain of 2." Materials Science and Technology 21(12): 1407-1411.

Commercial purity Al AA1200 cold rolled to a true strain 2 was annealed at 270°C for a series of times. The microstructural parameters Vv, the volume fraction recrystallized, Sv, the interfacial area density separating recrystallised grains from deformed matrix and < lambda >, the mean chord length of recrystallising grains, were measured stereologically using the EBSD technique. The recrystallisation kinetics were studied and the growth rates calculated by the extended Cahn-Hagel equation. It was found that the recrystallisation kinetics exhibited a two stage behaviour: an early stage characterised by decreasing growth rates, and a later stage with approximate constant growth rates. On average cube grains grow about two times faster than other grains and the growth rates of the three rolling texture components, brass, copper and S, are almost the same.




174.    Wu, G. L., A. Godfrey, et al. (2001). "Macroscopic subdivision of columnar grain aluminum with uv0 orientations following low strain deformation." Scripta Materialia 45(10): 1117-1122.




175.    Wu, G. L., A. Godfrey, et al. (2002). Texture and Deformation Structure Evolution during Rolling of Individual Grains of Columnar Grain Nickel. ICOTOM 13, Seoul, Korea, Trans Tech Publications Inc.

Columnar grain nickel with a strong <100> fibre texture, cut in slices taken parallel to the columnar grain direction, was cold-rolled to reductions of 10%, 30%, and 50%. Since each slice has the same starting grain structure and orientations, the texture evolution of individual grains with different initial orientations grains in a polycrystalline environment can be followed in a convenient manner. The deformation microstructure was studied by electron chanelling contrast imaging and the crystal rotations studied using the electron back-scatter pattern technique. Grain-scale deformation bands were observed on the rolling surface only for near cube-oriented grains. Comparison of texture evolution in grains with initial similar orientations shows that the deformation behaviour can be influenced by both grain orientation and grain interaction.




176.    Wu, G. L., A. Godfrey, et al. (2005). "Deformation strain inhomogeneity in columnar grain nickel." Scripta Materialia 53: 565-570.

A method is presented for determination of the local deformation strain of individual grains in the bulk of a columnar grain sample. The method, based on measurement of the change in grain area of each grain, is applied to 12% cold rolled nickel. Large variations are observed in the local strain associated with each grain.




177.    Wu, G. L., A. Godfrey, et al. (2005). The Orientations of Nuclei at Triple Junctions in Deformed Columnar Grain Ni. Textures of Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.

Ni with columnar grain was cold rolled and then recrystallized. The orientations at triple junctions before and after annealing were characterised using the EBSD technique, and recrystallization nuclei at triple junctions were identified. A comparison was made between the orientations of the nuclei and the orientations of the grains in the same area before annealing. Both nuclei with orientations within the orientation spread of the deformed grains as well as away from that were found.




178.    Wu, G., W. Liu, et al. (2004). "Experimental observation and modelling of the orientation evolution of individual grains in columnar grain Ni during cold rolling." Acta Metallurgica Sinica (China) 40(8): 785-790.

Columnar grain Ni samples with initial {001}(UV0) orientations were cold rolled to reductions of 0%, 10%, 30% and 50%, respectively. By using EBSP (electron back scattering pattern) technique, the orientation evolution of individual grains during rolling was followed, and the statistic results of grain rotation were obtained. A Taylor model was used to simulate the orientation evolution of each grain, and the modelled results were compared with observed results. It is found that the orientation evolution of individual grains during rolling is mainly effected by its initial orientation, and only a part of grains follow the evolution rule described by the Taylor model.




179.    Wu, H., S. C. Speller, et al. (2003). Microstructure control in the growth of large area Tl-2212 thin films. High Temp. Superconductivity Group Department of Materials University of Oxford, Oxford OX1 3PH, United Kingdom, Houston, Texas, USA.

Large area high temperature superconducting thin films are needed for the implementation of a range of passive microwave devices. We have been investigating the critical processing Issues that control the surface resistance values in 2 inch films grown on lanthanum aluminate substrates, including the possibility of batch processing wafers in a vertical geometry. We have shown that the microstructure of vertically-processed films shows a systematic variation in microstructure from top to bottom which can seriously degrade the uniformity of the superconducting properties. We have also used electron backscattered diffraction to analyze the fine-scale mosaic structure of thin films of varying thickness and processing conditions to show that the best surface resistance values are not found in films with the sharpest epitaxial relationship between the substrate and film. We propose an explanation for this counterintuitive observation based on how the films can relieve stresses generated during processing. 12 Refs.




180.    Wu, J., P. J. Wray, et al. (2003). Microstructure characterization of the austenite decomposition of HSLA steel strip. Symposium on the Thermodynamics, Kinetics, Characterization and Modeling of: Austenite Formation and Decomposition

2003, Chicago, Illinois, Minerals, Metals and Materials Society (TMS).

An important aspect of the thermomechanical processing of HSLA steel is the decomposition behavior of the deformed austenite, which has a great influence on the final microstructure and mechanical properties. In the present work, three commercial 490 MPa (70 Ksi) HSLA steels with different microalloying additions (Mb, Nb+V, Nb+Ti) were investigated. The influence of the prior metallurgical condition of the austenite and its decomposition behavior were studied using dilatometry, and metallographic techniques such as optical microscopy as well as TEM, SEM and EBSD The nature and variability of the decomposition products of the three steels were clearly identified and classified through the use of special etching techniques and grain boundary characteristics.




181.    Wu, K., S. S. Wang, et al. (2004). "The fabrication and high temperature stability of biaxially textured Ni tape by ion beam structure modification method." Physica C 412-414(Part 1): 240-245.

For the conventional rolling assisted biaxially textured metallic substrate (RABiTS) process, a large degree of cold rolling deformation and a subsequent high temperature annealing procedure are required to obtain adequately biaxially textured Ni tape. Recently, we have reported a newly developed process, named as ion beam structure modification (ISM), for fabricating biaxially textured Ni tape by use of low energy argon ion beam bombardment. In this paper, the biaxial texture of ISM processed Ni tape and its thermal stability at high temperatures are investigated. Results show that Ni tape processed under optimum ISM conditions, the (2 0 0) rocking curve FWHM is less than 5.7°, and the (1 1 1) Φ-scan FWHM is less than 7.5°. High temperature annealing does not impair the biaxial-texture already developed in ISM processed Ni foils, although ISMs should not be regarded as a complete equilibrium process.




182.    Wu, P. D. and D. J. Lloyd (2003). Formation of surface recrystallization of Al-Mg-Si alloy during extrusion. Metallurgical Modeling for Aluminum Alloys. Proceedings from Materials Solutions Conference 2003. 1st International Symposium on Metallurgical Modeling for Aluminum Alloys, Pittsburgh, PA, USA, ASM International.

The development of surface topography during plastic straining is important in many aspects of a materials performance, including aspects of formability and fracture, as well as surface appearance. In this paper plastic deformation induced surface roughening is simulated using the finite element method, which is based on crystal plasticity and directly incorporates measured EBSD (grain orientations and their spatial distributions). The effects of initial texture and its spatial distribution on the development of roughness are discussed.




183.    Wu, P. D. and D. J. Lloyd (2003). Modelling surface roughening with crystal plasticity. Materials Solutions Conference 2003, Pittsburgh, PA, USA, ASM International.

The development of surface topography during plastic straining is important in many aspects of a materials performance, including aspects of formability and fracture, as well as surface appearance. In this paper plastic deformation induced surface roughening is simulated using the finite element method, which is based on crystal plasticity and directly incorporates measured EBSD (grain orientations and their spatial distributions). The effects of initial texture and its spatial distribution on the development of roughness are discussed.




184.    Wu, P. D. and D. J. Lloyd (2004). "Analysis of surface roughening in AA6111 automotive sheet." Acta Materialia 52(7): 1785-1798.

The finite element method is used to numerically simulate the topographic development in an aluminium sheet, AA6111, under stretching. The measured electron backscatter diffraction (EBSD) data are directly incorporated into the finite element model and the constitutive response at an integration point is described by the single crystal plasticity theory. The effect on surface roughening of sample geometry, strain rate sensitivity, work hardening, imposed deformation path, as well as the EBSD step size, spatial orientation distribution and inhomogeneous deformation within individual grains are discussed. It is concluded that surface roughening is controlled by the spatial distribution of grain orientations through the thickness of the specimen. Copyright 2004 Acta Materialia Inc. All rights reserved.




185.    Wu, P. D., D. J. Lloyd, et al. (2003). "Analysis of roping in AA6111 automotive sheet." Acta Materialia 51(7): 1945-1957.

The finite element method is used to numerically simulate the development of roping in an aluminium sheet AA6111 under stretching. The measured EBSD data are directly incorporated into the finite element model and the constitutive response at an integration point is described by the single crystal plasticity theory. The effects of spatial orientation distribution, imposed deformation path, loading direction, and inhomogeneous deformation within individual grains on the roping are discussed. Correlation between roping and individual texture components is also explored.




186.    Wu, P. D., D. J. Lloyd, et al. (2003). "A simple model describing roping in A1 sheet." Scripta Materialia 48: 1243-1248.

A simplified method for analyzing the development of roping is proposed based on the observation that the initial texture and its spatial distribution are the predominant factors for roping. The method is validated by comparing its results with experimental observations, and with numerical results based on the finite element method.




187.    Wu, S. H., J. C. Huang, et al. (2004). "Evolution of Microstructure and Texture in Mg-Al-Zn Alloys during Electron-Beam and Gas Tungsten Arc Welding." Metallurgical and Materials Transactions A 35A(No. 8): 2455-2469.

The evolution of microstructure and texture in the AZ-series Mg alloys subjected to electron-beam welding and gas tungsten arc welding are examined. Electron-beam welding is demonstrated to be a promising means of welding delicate Mg plates, bars or tubes with a thickness of up to 50 mm; gas tungsten arc welding is limited to lower-end thin Mg sheets. The grains in the fusion zone (FZ) are nearly equiaxed in shape and ~8 µmor less in size, due to the rapid cooling rate. The as-welded FZ microhardness and tensile strength are than the base metals due to the smaller grain size. The weld efficiency, defined as the postweld microhardness or tensile strength at the mid-FZ region divided by that of the unwelded base metal, is around 110 to 125 pct for the electron-beam welding and 97 to 110 pct for gas tungsten arc welding. There are three main texture components present in the electon-beam welded (EBW) FZ, ie., {1011}<1012> (with TD//<;1120>, {1121}<1100> (with ND^<1120>~15 deg), and {1010}<1122> (with WD^<1120>~30 deg), where TD, ND, and WD are the transverse, normal and welding directions, respectively. The crystal growth tends to align toward the most closed-packed direction, <1120>. The texture in gas tungsten arc welded (GTAW) specimens is more diverse and complicated than the EBW counterparts, due to the limmited and shallow FZ and the lower cooling rate. The cooling rates calculated by the three-dimensional (3-D) and two-dimensional (2-D) heat-transfer models are considered to be the lower and upper bounds. The cooling rate increases with decreasing Al content, increasing weld speed, and increasing distance from the weld top surface. The influences of the FZ location, welding speed, and alloy content on the resulting texture components are rationalized and discussed.




188.    Wu, S. J. and C. L. Davis (2004). "Investigation of the microstructure and mesotexture formed during thermomechanical controlled rolling in microalloyed steels." Journal of Microscopy 213(Pt 3): 262-272.

Thermomechanical controlled rolling (TMCR) has been widely used as an effective method to improve the properties of steels. In the present paper, two commercial TMCR microalloyed steels were investigated. The grain size distributions and grain boundary misorientation angles were measured using electron backscattered diffraction patterns obtained using orientation imaging microscopy (OIM). The equivalent grain diameters were also measured using optical microscopy. Mixed coarse- and fine-grained regions were observed and the microhardness values were measured for both areas. Grain boundary misorientation angle distributions showed that the magnitude of mesotexture developed in the steel is dependent upon the rolling passes, the reduction ratio and the rolling temperatures including the finish rolling temperature. The surface layer, up to 2 mm depth, in Com-A steel had about 55% of grain boundaries with a misorientation angle below 12 degrees, much higher than in the central area (approximately 30%), whereas Com-B steel showed similar distributions from the rolling surface to the centre. Misorientation results obtained from laboratory rolled steel plates with various TMCR procedures are also discussed as are OIM results from Charpy impact brittle fracture surfaces examining the effect of misorientation on crack propagation.




189.    Wu, T. K., W. Liu, et al. (2005). "Effects of an external electric field on cube texture development of rolled pure nickel during recrystallization." Materials Letters 59(11): 1365-1368.

The effects of an external electric field on cube texture development have been studied by means of electron backscatter pattern technique, using rolled nickel sheets of 99.999% purity. Samples were annealed at 300 deg C for different times both without and with an external electric field, of intensity 2000 V/cm. Results show that the application of an external electric field has decreased the volume fraction of cube texture and the grain size of cube oriented grains.




190.    Wuhrer, R., K. Moran, et al. (2004). X-ray Mapping and Electron Back Scattered Diffraction of Phases in Welded Materials. Microscopy and Microanalysis 2004, Savannah, Georgia, USA, Cambridge University Press.

There have been a number of new bonding/welding processes developed that allow the joining of very dissimilar materials such as wear resistant white irons, cast irons, non-ferrous alloys and ceramic materials to mild steel, as well as allowing more complex composite shapes to be produced. However, with any new process development, an understanding of the mechanism of bonding is required.




191.    Wulff, F., C. D. Breach, et al. (2003). "Crystallographic texture of drawn gold bonding wires using electron backscattered diffraction (EBSD)." Journal of Materials Science 22(19): 1373-1376.

Gold ball bonding wire is used as an interconnection between die pads and substrates in over 90% of worldwide semiconductor assemblies. Typical wire thicknesses in consumer applications are 20-25 mu m with an increasing trend towards the use of 12-15 mu m wires forecast for the near future. The end of the wire is melted into a ball using an electric arc on a wirebonding machine and the ball is then thermosonically welded to the die pad metallization (which is usually 0.7-1.0 mu m thick Al with Cu and/or Si minor additions). The thermosonic welding is performed at frequencies from 60-140 kHz and at temperatures of 150-250'C. The melting of the end of the wire results in a temperature gradient along the wire length that causes a variation in properties over a region called the heat-affected zone (HAZ). The region after the HAZ has the normal properties of the wire. After the ball has been bonded, the wire is then formed into a controlled-profile loop that is thermosonically welded to the substrate, thus forming an electrical connection between die and substrate. A significant factor in loop control is the HAZ length that determines where the wire bends and characterization of the HAZ is an essential part of bonding wire development. Gold bonding wire is produced by a wire drawing process that develops a preferred (111) texture in the drawing direction. In wire form, gold, being anisotropic therefore tends to be stronger in the drawing direction. In addition to the mechanically induced texture of gold bonding wire, the wire has additions of various elements to a maximum of 100 ppm by weight (4N or 99.99% purity gold) to control strength, modulus and recrystallization behavior.




192.    Wusatowska-Sarnek, A. M., J. Miura, et al. (2002). "Nucleation and microtexture development under dynamic recrystallization of copper." Materials Science and Engineering 323(1-2): 177-186.

Microstructure and microtexture evolution during dynamic recrystallization (DRX) was investigated in compression of polycrystalline copper in the temperature range from 473 K to 723 K and at strain rates from 10−3s−1 to 10−1s−1. A compression texture of near <101> direction, evolved by low temperature deformation, is gradually weakened and randomized by the progress of DRX at higher temperature, where <101> component still exists. New DRX grains are evolved by the operation of bulging of serrated grain boundaries, which is accompanied either by rotation of a bulged portion or twinning at the back of the migrating boundary. The mechanisms of dynamic nucleation and necklace DRX are discussed.




193.    Wynblatt, P., G. S. Rohrer, et al. (2003). "Grain boundary segregation in oxide ceramics." Journal of the European Ceramic Society 23: 2841-2848.

The factors which control grain boundary segregation in oxide ceramics are reviewed. These include grain boundary energy, cation–cation interactions, impurity cation size, as well as electrostatic interactions with the grain boundary space charge. In addition, an approach for measuring grain boundary segregation in those materials, as a function of the five macroscopic parameters of grain boundary character, is described. This experimental method relies on the coupled application of orientation imaging microscopy and scanning Auger spectroscopy.




194.    Wynick, G. L. and C. J. Boehlert (2005). "Electron backscattered diffraction characterization technique for analysis of a Ti2AlNb intermetallic alloy." Journal of Microscopy 219(3): 115-121.

This investigation was conducted to ascertain the benefits of electropolishing after mechanical polishing for electron backscattered diffraction of a Ti2AlNb intermetallic Ti-21Al-29Nb (at.%) alloy containing the orthorhombic (O) and body-centered-cubic (BCC) phases. Electropolishing was performed at -40°C in 6% H2SO4methanol solution. Atomic force microscopy was used to measure the surface topography in attempt to correlate nano-scale surface roughness with electron backscatter diffraction pattern quality. The results suggest that mechanically polishing with colloidal silica (Si02) or alumina followed by electropolishing is a sufficient surface preparatory technique for producing quality electron backscattered diffraction patterns for O + BCC microstructures. However, poor pattern quality results after mechanically polishing without electropolishing. High- quality orientation maps for O-dominated O + BCC microstructures were only possible through mechanical polishing followed by electropolishing. The data also suggest that surface roughness, on the order of 50 nm, has less effect on pattern quality than subsurface deformation. Overall, removing the near-surface amage was more critical than reduction of topography.




195.    Wynick, G. L. and C. J. Boehlert (2005). "Use of electropolishing for enhanced metallic specimen preparation for electron backscatter diffraction analysis." Materials Characterization 55(3): 190-202.

The effects of mechanical polishing with Al2O3 and colloidal SiO2 followed by electropolishing were studied for preparation of metal alloy specimens for Electron Backscatter Diffraction (EBSD). The alloys studied were Inconel 718, a commonly used nickel-based superalloy, and a Ti-Al-Nb alloy (nominally Ti-22Al-28Nb(at.%)). Atomic Force Microscopy was used to measure the surface topography to attempt to correlate nano-scale surface roughness with EBSD pattern quality. The results suggest that mechanically polishing with Al2O3 followed by electropolishing for a short time can produce EBSD pattern confidence indices and image quality values that are equal to or better than those produced by mechanically polishing with colloidal SiO2 alone. The data suggests that surface roughness on the scale considered here has much less effect on EBSD pattern quality than had been previously believed. The data suggests that removing the surface damage is more critical than reduction of topography for EBSD for EBSD.




195 records found

 

 

  
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