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46 records found
1.
Eades, A. (2000). EBSD: Buying a System. Electron Backscatter Diffraction in
Materials Science. A. J. Schwartz, M. Kumar and B. L. Adams. New York,
Kluwer Academic/Plenum Publishers: 123-6.
2.
Eades, A. (2003). "Electron backscattering diffraction: pushing the
limits." Scanning 25(2): 82.
3.
Eardley, E. S., A. Soulet, et al. (2003). Microstructure and Plastic
Anisotropy in rolled Al-Mg alloys. Thermec' 2003, Leganés, Madrid,
Spain, Trans Tech Publications Ltd.
The directionality of tensile behavior in cold rolled AA5005 (~1%Mg) and
AA5182(~5%Mg) alloys has been investigated. Both the materials initially had
a 'cube' texture, that in the AA5005 being significantly stronger. At
rolling strains up to 0.5, the cube texture remained dominant in both
alloys. In the AA5005 there was a marked dependence of mechanical behavior
on the degree of prior rolling strain and on the direction of the tensile
axis relative to the rolling direction. Part of the directionality was due
to crystallographic texture effects, notably the contribution to work
hardening- and so elongation- from the change in referred orientation
occurring in tension at 45° to the rolling direction. There was also a
significant difference in plastic behavior between tension at 0° and
90° to the rolling direction, caused by the directionality in
deformation substructure generated during the rolling which led to
characteristic strain path change effects. Static recovery was found to
affect the work hardening and ductility of the samples, and this is thought
to be due to substructural condensation. The overall behavior of AA5005 was
quite similar to that reported for commercial purity AA1200. However, in
AA5182, such strain path effects were not observed for the pre-strains
investigated. This is due to the lack of a well developed aligned
substructure in this material caused by the effect of magnesium solute on
dynamic recovery.
4.
Eaton, H. C., J. C. Carter, et al. (1982). "Topographic Analysis of
Grain-Boundary Dislocations in Cold-Worked Tungsten Using Field-Ion
Microscopy." Physica Status Solidi A 72(2): 817-824.
5.
Eberhardt, A. and B. Baudelet (1980). "Interphase Boundary Sliding at
High-Temperature in 2 Phase Alpha-Beta-Brass Bicrystals." Philosophical
Magazine A 41(6): 843-869.
6.
Ebrahimi, R., A. Oudin, et al. (2004). Static Recrystallization of Ti-IF
Steel after Warm Deformation. Second Joint International Conference on
Recrystallization and Grain Growth, ReX & GG2, SF2M, Annecy, France,
Trans Tech Publications Ltd.
The present work examines the effect of strain and Zener Hollomon parameter,
Z, on deformation and recrystallization of Ti-IF steel deformed in the warm
temperature region. Torsion tests were performed at temperatures of 765 deg
C and 850 deg C and strain rates of 0.003s-1 and 1s-1.
For some conditions, an annealing treatment at the temperature of
deformation was carried out using a fluidized bed furnace. Electron Back
Scatter Diffraction (EBSD) maps were implemented to study the microstructure
evolution. At a low value of Z abnormally large grains formed during
annealing. At the higher values of Z, a more classical recrystallization
reaction occurred during annealing. The latter is more desirable in most
commercial applications.
7.
Eckert, D., O. Gutfleisch, et al. (2003). "Local texture in Nd-Fe-B
sintered magnets with maximised energy density." Journal of Alloys and
Compounds 365(1-2): 259-265.
Sintered Nd-Fe-B magnets, one of which showed a maximised energy density as
high as (BH)max=451 kJ/m3 (56.7 MGOe) at room
temperature, have been produced by optimisation of alloy composition,
minimisation of impurities, improved alignment of the powder particles and a
controlled sintering process. For the first time, large scale microtexture
analysis using electron backscatter diffraction (EBSD) has been carried out
on sintered Nd-Fe-B magnets. Large orientation maps in both directions,
parallel and perpendicular to the texture axis, were acquired in a thermal
field emission gun scanning electron microscope (FEGSEM). Domain patterns of
the same areas have been obtained using magneto-optical Kerr-microscopy.
Thereby, a quantitative description of local texture could be correlated
effectively with domain patterns of individual grains and with backscattered
electron images. Distinction between individual grains in the Kerr-images
was more difficult due to the excellent alignment of the grains in the
magnet with the maximised energy density. Pole figures were used to evaluate
EBSD patterns. Copyright 2003 Elsevier B.V. All rights reserved.
8.
Edahl, R. A., Jr. (2005). "Determination of grain orientation in an
aluminum-lithium alloy using the polarized light microscope."
Microscope 53(1): 21-28.
this paper deals with the surface anodizing technique to reveal the grain
structure of aluminium-lithium alloy. The preferred grain orientation and
orientation of the individual grain of the specimen can be determined by
using polarized light microscopy, electron microscopy and electron
backscatter diffraction analysis.
9.
Eddahbi, M., J. A. d. Valle, et al. (2005). "Comparison of the
microstructure and thermal stability of an AZ31 alloy processed by ECAP and
large strain hot rolling." Materials Science and Engineering A
410-411: 308-311.
The aim of this work is to compare the microstructure, the texture, as well
as the thermal stability of an AZ31 Mg alloy processed via two different
severe plastic deformation processing techniques, namely large strain hot
rolling (LSHR) and equal channel angular pressing (ECAP). The microstructure
was characterized by optical microscopy and the texture was measured both by
X-ray diffraction and electron backscatter diffraction (EBSD). The
microstructure obtained via LSHR has average grain sizes around 3 μm,
but it is quite heterogeneous. Additionally, a well-defined basal texture
develops. ECAP gives rise to a more homogeneous and slightly coarser
microstructure, with an average grain size of 7 μm and a shear type
texture. The higher resistance of the extruded sample to secondary
recrystallization after severe post-deformation annealing is attributed to a
texture effect.
10.
Edington, J. W. (1981). "Dislocation-Motion, Grain-Boundary Sliding and
Structural Superplasticity." Metals Forum 4(1-2): 63-68.
11.
Edington, J. W. (1982). "Microstructural Aspects of
Superplasticity." Metallurgical Transactions A 13(5):
703-715.
12.
Eghbali, B. and A. Abdollah-Zadeh (2006). "Strain-induced
transformation in a low carbon microalloyed steel during hot compression
testing." Scripta Materialia 54(6): 1205-1209.
Strain-induced transformation (SIT) of austenite to ferrite during hot
compression testing of a low carbon microalloyed steel is investigated by
using optical microscopy and electron back-scattered diffraction.
Microstructural observation indicates that ultrafine ferrite grains of 1.5
μm can be obtained by deformation at 845 °C, just above
Ar3, with a strain rate of 0.1 s−1 due to the
occurrence of SIT of austenite to ferrite.
13.
Eickemeyer, J., D. Selbmann, et al. (2004). "Nickel DABiTS-tapes as a
promising alternative to RABiTS-tapes." Physica C 408-410:
906-907.
Drawing of nickel through wedge shaped dies as well as through loose rolls
with subsequent annealing was performed in order produce a sharp
recrystallisation cube texture. The drawing/annealing processing was very
effective and the obtained tapes were designated as DABiTS.
14.
El Wahabi, M., L. Gavard, et al. (2005). "EBSD study of purity effects
during hot working in austenitic stainless steels." Materials Science
and Engineering A 393(1-2): 83-90.
The technique of electron back scattering diffraction (EBSD) is considered
as a powerful instrument for the study of the microstructural changes during
hot forming processes and gives the possibility to present the information
in different ways (OIM, misorientation diagram and pole figures). The
present work is focused on the observation by EBSD of the microstructure
evolution during deformation at high temperature of three austenitic
stainless steels: AISI-304H, AISI-304L and a high purity steel HP. The
difference between the three steels is the content carbon and the presence
of residual elements. To this aim compression tests were carried out at a
constant strain rate of 0.001 s-1 and different temperatures. The
study showed an increase of twin boundary fractions and a diminution of
substructure (low angle densities boundaries) at increasing temperatures. On
the other hand, increasing carbon content promotes lower twin boundary
fractions and larger amounts of low angle boundaries. This effect can be
explained by the reduction of grain boundary mobility caused by increasing
carbon contents, which in turn reduces the migration rate and consequently
the probability of twin boundary generation. Moreover, the increment of low
angle boundaries with carbon content accelerates the twin character loss. It
was also found that the dynamically recrystallized grain size decreased at
increasing carbon content due to a typical drag effect. No important
features on textures were found during DDRX. Copyright 2004 Elsevier B.V.
All rights reserved.
15.
El Wahabi, M., L. Gavard, et al. (2005). "Effect of initial grain size
on dynamic recrystallization in high purity austenitic stainless
steels." Acta Materialia 53(17): 4605-4612.
The influence of initial microstructure on discontinuous dynamic
recrystallization (DDRX) has been investigated by using high purity and
ultra high purity austenitic stainless steels with various initial grain
sizes. After uniaxial compression tests at constant strain rates and various
temperatures, the steady state microstructure or the state corresponding to
the maximum strain (ε = 1) attained in the test was analyzed by
scanning electron microscopy aided with automated electron back scattering
diffraction. Recrystallized grain size drec and twin boundary
fraction fTB measurements were carried out. The mechanical
behavior was also investigated by comparing experimental stress–strain
curves with various initial grain sizes. DDRX kinetics was described by the
classical Avrami equation. It was concluded that larger initial grain sizes
promoted a delay in the DDRX onset in the two alloys. It was also observed
that the softening process progressed faster for smaller initial grain
sizes. The effect of initial grain size is larger in the HP material and
becomes more pronounced at low temperature.
16.
El-Dasher, B. S. and A. D. Rollett "A Methodology for Fully
Characterizing an EBSD Based Orientation Mapping System."
The significant increase in popularity in recent years of Orientation
Mapping based on automated electron backscatter diffraction (EBSD) has in
large part been because of its flexibility as a microstructure
characterization tool. As with any method, however, it is always wise to be
skeptical about the accuracy of the results. Prior accuracy investigations
have focused on two critical aspects of the methodology: spatial resolution,
and indexing accuracy as defined by angular resolution. This paper
investigates these parameters for characterizing accuracy, suggests a novel
approach to characterizing the angular resolution of a system, and proposes
a set of tests that should be carried out on EBSD systems in order to
comprehensively quantify their accuracy.
17.
El-Dasher, B. S. and S. G. Torres (2004). "Effect of stress mitigation
on precipitation kinetics in alloy 22 welds." JOM 56(11):
306.
Understanding the phase stability of Alloy 22 (N06022) is important since
the precipitation of tetrahedrally close-packed (TCP) phases over time has
been known to adversely affect corrosion and mechanical properties. Prior
observations have shown that these phases precipitate during the welding
process. After welding, residual stresses due to the solidification and
cooling from temperature remain. When the weld cannot be stress-relieved by
solution annealing, the application of commercially available
stress-mitigation processes such as low plasticity burnishing (LPB) and
laser shock peening (LSP) may be used to produce near-surface compressive
stresses. This study involved examination of cross-sectional samples of aged
1.25'' thick welds of Alloy 22 plates using electron backscatter diffraction
(EBSD) for TCP identification, and micrograph analysis for TCP
quantification. Precipitation in the LSP treated weld was observed primarily
in inter-dendritic regions, similar to that in the as-welded material.
Precipitation in the LPB treated weld however was observed in both
inter-dendritic as well as intra-dendritic regions.
18.
El-Dasher, B. S., B. L. Adams, et al. (2003). "Viewpoint: experimental
recovery of geometrically necessary dislocation density in
polycrystals." Scripta Materialia 48(2): 141-145.
Application of electron backscattering diffraction methods to recover
estimates of of the geometrically necessary dislocation density is
described. The limitations of the method arising from the opacity of
crystalline materials and the spatial and angular resolution limits are
discussed. copyright 2002 Acta Materialia Inc., Published by Elsevier
Science Ltd. All rights reserved.
19.
El-Dasher, B. S., H. M. Miller, et al. (2004). Distribution of grain
boundary planes at coincident site lattice misorientations. Interfacial
Engineering for Optical Properties III, San Francisco, California, USA,
Materials Research Society.
The grain boundary plane distributions in MgO, SrTiO3,
MgAl2O4, and Al are compared at lattice
misorientations with a coincident site density of greater than or equal to
1/9. In most situations, the most frequently adopted grain boundary
orientation is a habit plane of low index and low surface energy that
depends on the particular material. Cases where the most common boundary
orientation is a plane of high planar coincident site density instead of a
characteristic habit plane are rare. In fact, in most cases, the
distributions of grain boundary planes at misorientations with high lattice
coincidence are not substantially different from the distributions at other,
more general misorientations. The results indicate that a model for grain
boundary energy and structure based on grain surface relationships is more
appropriate than the widely accepted models based on lattice orientation
relationships.
20.
El-Dasher, B. S., R. A. Etien, et al. (2006). Effect of Solution Annealing
Temperatures on the Crevice Corrosion Mode of Alloy 22. CORROSION NACExpo
2006 61st Annual Conference & Exposition, San Diego, California,
USA.
The effect of solution annealing temperature on the observed corrosion
attack mode in Alloy 22 welds was assessed. Three types of specimens were
examined, including the as-welded state, solution annealed for 20 minutes at
1121DGC, and solution annealed for 20 minutes at 1200DGC. The
microstructures of the specimens were first mapped using electron
backscatter diffraction to determine the grain structure evolution due to
solution annealing. The specimens were then subjected to electrochemical
testing in a 6 molal NaCl + 0.9 molal KNO3 environment to initiate crevice
corrosion. Examination of the specimen surfaces after corrosion testing
showed that in the as-welded specimen, corrosion was present in both the
weld dendrites as well as around the secondary phases. However, the specimen
solution annealed at 1121DGC showed corrosion only at secondary phases and
the specimen annealed at 1200DGC showed pitting corrosion only in a handful
of grains.
21.
El-Dasher, B. S., S. G. Torres, et al. (2004). Identification and
Quantification of Topologically Close Packed Phases (TCP) in Alloy 22 Using
Electron Backscatter Diffraction (EBSD) Analysis. Microscopy and
Microanalysis 2004, Savannah, Georgia, USA, Cambridge University
Press.
The choice of Alloy 22 (UNS #N06022), a Ni-Cr-Mo alloy, as a candidate
material for the nuclear waste package in the Yucca Mountain Project has
prompted extensive studies ranging from corrosion to phase stability. Since
the waste package is intended to last ten thousand years, a computational
model was necessary to simulate the metallurgical changes the material would
experience during that period of time [1]. This is especially important with
respect to the phase stability of the welds since three distinct phases can
precipitate out of the matrix, and have been known to affect the material
properties in similar Ni-Cr-Mo alloys [2,3]. As with all models,
experimental verification is an integral part in determining the suitability
of the assumptions used.
22.
El-Dasher, B. S., T. S. Edgecumbe, et al. (2006). "The Effect of
Solution Annealing on the Microstructural Behavior of Alloy 22 Welds."
Metallurgical and Materials Transactions A 37(3): 1027-1028.
Multipass gas tungsten arc welds of alloy 22 were subjected to solution
annealing durations of 20 minutes, 24 hours, 72 hours, and 1 week at
temperatures of 1075 DGC, 1121 DGC, 1200 DGC, and 1300 DGC. The specimens
were studied in cross section by secondary electron microscopy to determine
the effect of solution annealing on tetrahedrally close-packed (TCP)
precipitate stability. Electron backscatter diffraction mapping was also
performed on all of the specimens to determine the recrystallization
behavior of the welds. It was found that complete TCP precipitate
dissolution occurs after solution annealing at 1075 DGC and 1121 DGC for 24
hours, and at 1200 DGC and 1300 DGC for durations of 20 minutes. Regions of
most rapid recrystallization were correlated to the regions of lowest solute
content, highest plastic strain, and highest residual stresses. Texture
analysis indicated that while the columnar dendrites originally present in
the weld grew with a < 001 > orientation in the transverse direction
(approximately opposite the heat flow direction), the recrystallized grains
adopt a < 101 > orientation in the transverse direction when
recrystallization and TCP phase dissolution occur simultaneously.
23.
El-Naggar, M. Y., D. A. Boyd, et al. (2005). "Characterization of
highly-oriented ferroelectric
PbxBa1−xTiO3 thin films grown by
metalorganic chemical vapor deposition." Journal of Materials Research
20(11): 2969.
PbxBa1−xTiO3 (0.2 </= x </= 1)
thin films were deposited on single-crystal MgO as well as amorphous
Si3N4/Si substrates using biaxially textured MgO
buffer templates, grown by ion beam-assisted deposition (IBAD). The
ferroelectric films were stoichiometric and highly oriented, with only (001)
and (100) orientations evident in x-ray diffraction (XRD) scans. Films on
biaxially textured templates had smaller grains (60 nm average) than those
deposited on single-crystal MgO (300 nm average). Electron backscatter
diffraction (EBSD) has been used to study the microtexture on both types of
substrates and the results were consistent with x-ray pole figures and
transmission electron microscopy (TEM) micrographs that indicated the
presence of 90° domain boundaries, twins, in films deposited on
single-crystal MgO substrates. In contrast, films on biaxially textured
substrates consisted of small single-domain grains that were either c or a
oriented. The surface-sensitive EBSD technique was used to measure the
tetragonal tilt angle as well as in-plane and out-of-plane texture.
High-temperature x-ray diffraction (HTXRD) of films with 90° domain
walls indicated large changes, as much as 60%, in the c and a domain
fractions with temperature, while such changes were not observed for
PbxBa1−xTiO3 (PBT) films on biaxially
textured MgO/Si3N4/Si substrates, which lacked 90°
domain boundaries.
24.
Engler, O. (1997). On the Influence of Dispersoids on the Particle
Stimulated Nucleation of Recrystallization in an Al-Fe-Si Model Alloy.
International conference on textures and anisotrohy of polycrystals,
Germany.
The recrystallization of Al-alloys is controlled by precipitates. Whereas
large particles generally promote recrystallization by particle stimulated
nucleation, finely dispersed precipitates - either already present in the
as-deformed state or precipitating during the recrystallization anneal - are
known to strongly retard recrystallization. It was the aim of the present
study to elucidate these concurring effects of large particles and small
dispersoids on recrystallization in a ternary Al-Fe-Si model alloy. For that
purpose, samples were prepared according to different pre-annealing
treatments so as to comprise different states of precipitation and
supersaturation. The evolution of microstructure and texture during rolling
and recrystallization was characterized by metallography and by conventional
X-ray texture analysis. EBSD-local texture investigations were employed to
yield information on the efficiency of nucleation at the various nucleation
sites and, consequently, on the influence of dispersoids on
recrystallization.
25.
Engler, O. (1998). "On the influence of orientation pinning on growth
selection of recrystallisation." Acta Materialia 46(5):
1555-68.
In summary, a technique has been presented that allows the habit planes of
known phase transformations to be determined in bulk samples. Although
developed to differentiate between the Isaichev and Bagaryatsky ORs in
pearlite, it can be applied to any microstructure where the possible
orientation relationships are known. The errors associated with this
technique are often as small as one degree, but depend on the distortion of
the gnomonic projection and the ability to precisely measure the orientation
of the habit plane. The technique is not as accurate as high angle tilting
in TEM for several reasons. The gnomonic projection has not been quantified
so the distortion of the diffraction patterns is a source of error. In
addition, only the apparent habit plane is traced from the micrograph
(similar to SAD in conventional TEM), and this may deviate from the atomic
habit plane by several degrees. Despite these limitations, it expands the
capabilities of EBSD and allows orientation relationships to be
unambiguously determined, for a transformation where more than one
orientation relationship is possible a major advantage over TEM is
statistical sampling. Many more habits can be determined using EBSD with
SEM. Indeed, every plate can be studied over one or many grains. (13
References).
26.
Engler, O. (1998). A Simulation of Recrystallisation Based on EBSD
Orientation Microscopy Data. Proceedings of the 19th Riso International
Symposium on Materials Science: Modelling of Structure and Mechanics of
Materials, Roskilde, Denmark, Riso National Laboratory.
The present paper introduces a novel stochastic two-dimensional model to
simulate the evolution of microstructure and texture during
recrystallization. The model is based on data derived by automated
large-scale EBSD local texture analysis, i.e., by orientation microscopy.
Each measured point is characterized by its coordinates x and y in the
microstructure, its crystallographic orientation g and a parameter q
describing the quality of the EBSD-pattern which is affected by lattice
strain and hence discloses information on the dislocation density. The
concurrent information on the local arrangement of orientations and
dislocation densities is utilized to derive conclusions on the nucleation
and subsequent growth of the new recrystallized grains. The principles of
the model are outlined and three example are shown to illustrate the
possibilities of the model to simulate the evolution of microstructure and
texture during recrystallization.
27.
Engler, O. (2001). "An EBSD local texture study on the nucleation of
recrystallization at shear bands in the alloy Al-3%Mg." Scripta
Materialia 44(No. 2): 229-236.
28.
Engler, O. and G. Gottstein (1992). "A new approach in texture research
- Local orientation determination with EBSP." Steel Research
63(9): 413-418.
At present, computer-aided Electron Back Scattering Pattern (EBSP) analysis
often requires large amounts of operator time if statistically reliable
measurements are needed. The authors present ways to automatically detect
and localize bands in EBSPs and thereby enable fully automatic EBSP
analysis. The main focus is on a procedure using a modified Hough transform
by which more than 12 bands in a typical EBSP can be detected and localized.
This procedure seems as effective and reliable for extracting the bands of
EBSPs as any human operator. The performance of this procedure is compared
with that of other image processing procedures. (14 References).
29.
Engler, O., G. Gottstein, et al. (1993). Statistics, Evaluation and
Representation of Single Grain Orientation Measurements. ICOTOM 10,
Materials Science Forum.
Single grain orientation measurements of large contiguous volumes provide a
new basis for the understanding of microstructure evolution during materials
processing. With these techniques it became possible to determine the
distribution of orientations in correlation to the spatial arrangement of
the corresponding grains in the microstructure. The current paper briefly
summarises recent developments in microtexture evaluation. Various possible
ways of representation of single grain orientation data and of
misorientation data are discussed, and the advantages or disadvantages of
these forms of representation are demonstrated by means of various examples.
Procedures to evaluate the physical significance of microtexture data are
addressed.
30.
Engler, O., J. Hirsch, et al. (1995). "Texture Development in Al-l.8
wt% Cu Depending on the Precipitation State--II. Recrystallization
Textures." Acta Metallurgica y Materialia 43(1):
121-138.
The development of the recrystallization texture of the alloy AI-1.8 wt% Cu
was investigated by analysis of orientation distribution functions (ODF)
determined by X-ray diffraction, supported by metallography and EBSD local
texture analysis. In dependence on the degree of deformation, the annealing
temperature and, in particular, on the precipitation state a large variety
of recrystallization textures was found which could be subdivided into four
characteristic types. The differences between these recrystallization
texture types could be attributed to differences in the nucleation and
growth behaviour. From the present results general conclusions about the
various recrystallization mechanisms occurring in aluminum alloys can be
drawn.
31.
Engler, O., J. Jura, et al. (1999). Influence of number and arrangement of
single orientation measurements on their statistical relevance. Twelfth
International Conference on Textures of Materials (ICOTOM 12), McGill
University, Montreal, Canada, NRC Research Press.
32.
Engler, O., K. Lucke, et al. (1999). Recrystallization textures in
copper-manganese alloys. Twelfth International Conference on Textures of
Materials (ICOTOM 12), McGill University, Montreal, Canada, NRC Research
Press.
Manganese is the only alloying element that does not lower the (normalised)
stacking fault energy (SFE) of copper-alloys. Therefore, analysis of the
recrystallisation behaviour of Cu-Mn alloys may yield information on the
impact of solute atoms on the recrystallisation, independent of the
influence of the SFE. For this purpose the progress of recrystallisation is
tracked in various Cu-Mn alloys by hardness measurements and X-ray texture
investigations. To support the results obtained by macrotexture analysis,
and in particular to trace the origin of the recrystallisation texture
orientations, local orientation measurements are performed by means of
electron back scattering diffraction (EBSD). The recrystallisation textures
as well as data on the recrystallisation kinetics of the present Cu- Mn
alloys are compared to results obtained in other binary Cu-alloys.
33.
Engler, O., M.-Y. Huh, et al. (2005). "Crystal-Plasticity Analysis of
Ridging in Ferritic Stainless Steel Sheets." Metallurgical and
Materials Transactions A 36A(11): 3127-3139.
The occurrence of ridging in ferritic stainless steel (FSS) sheets is caused
by the collective deformation of bandlike clusters of grains with a similar
crystallographic orientation. In this article, large-scale (1.8 X 3.6 mm)
orientation maps obtained by electron backscattered diffraction (EBSD) are
input into a viscoplastic self-consistent polycrystal plasticity model to
analyze the strain anisotropy caused by the topographic arrangement of the
recrystallization-texture orientations. Two versions of the ridging model
were devised: (1) the local dispersion in strain-rate components is analyzed
for the full EBSD map, and (2) narrow bands in the EBSD maps aligned
parallel to the ridges on the sheet surface are considered, and the
variation in macroscopic strain response from band to band is derived. The
effects caused by spatial variations in through-thickness strains and in
out-of-plane shears are compared and related to ridging. The model is
applied to two sheets distinguished by different levels of ridging.
34.
Engler, O., P. Yang, et al. (1994). Behavior of Statistical Texture
Parameters Applied to Single Grain Orientation Measurements in
Recrystallized Al-Mn. Tenth International Conference on Textures of
Materials (ICOTOM 10), Clausthal, Germany.
35.
Engler, O., P. Yang, et al. (1996). Microtexture of Deformation Zones and
Particle Stimulated Nucleation withing Individual Rolling Texture Components
in Pure Al-1.3%Mn. Eleventh International Conference on Textures of
Materials, Xi'an, China, International Academic Publishers.
36.
Engler, O., P. Yang, et al. (1996). "On the Formation of
Recrystallization Textures in Binary Al-1.3% Mn Investigated by Means of
Local Texture Analysis." Acta Materialia 44(8):
3349-3369.
The development of the recrystallization textures of high purity Al-1.3% Mn
is analysed with dependence on the degree of deformation, the annealing
temperature and, particularly, the precipitation state prior to deformation.
Besides X-ray macrotexture analysis, local orientation measurements by
electron diffraction in a SEM (EBSD) and in a TEM (MBED) are applied. A
combination of these three techniques permits orientation determination with
increasing spatial resolution and yields a much more fundamental
understanding about the underlying recrystallization mechanisms than is
possible using solely one of these techniques. The recrystallization
textures are characterized by a competition between cube- oriented grains
which nucleate at band-like structures and grains due to particle stimulated
nucleation (PSN). The evolution of the resulting textures is discussed in
terms of formation and subsequent growth of the recrystallization
nuclei.
37.
Enomoto, M. and E. Furubayashi (1981). "Unstable Plastic-Flow and
Mechanical-Properties of Substitutional Iron-Alloys with Polygonized
Ultrafine Grain Microstructure." Transactions of the Iron and Steel
Institute of Japan 21(1): 47-53.
38.
Erben, N., S. Dabritz, et al. (1981). "Kossel Line-Profiles Near
Dislocations in Gap." Physica Status Solidi A 65(2):
K175-K178.
39.
Erben, N., S. Dabritz, et al. (1982). "Kossel Line Broadening Near a
Scratch on Gap." Physica Status Solidi A 72(1): K15.
40.
Erieau, P. and C. Rey (2002). Finite Element Modeling of the Intragranular
Reorientation and Stored Energy Induced by Deformation in an If-Ti Steel
Aggregate Submitted to Channel Die Compression. ICOTOM 13, Seoul, Korea,
Trans Tech Publications Inc.
An experimental deformation analysis of a grain aggregate is presented as
well as a finite element method (FEM) which enables to compute some
particular quantities which cannot be easily obtained experimentally, like
the stored energy of cold work. Comparisons are made between OIM
measurements after deformation and FEM results performed on a mesh that
matches exactly the original grain shapes and orientations before
deformation. A very good agreement is found, especially intragranular
microstructures are well predicted.
41.
Etter, A. L., D. Solas, et al. (2005). Evolution of microstructure and
texture during annealing of a copper processed by ECAE. Textures of
Materials - ICOTOM 14, Leuven, Belgium, Trans Tech Publications.
A submicron-grained (SMG) microstructure, with an average grain size of ~0.4
μm was produced by equal channel angular extrusion (ECAE). The SMG
microstructure was composed of large dynamic recrystallized grains within a
matrix of deformed elongated cells. Samples were annealed for various times
at 473 K and then examined using transmission electron microscopy (TEM) and
electron back scattered diffraction (EBSD). The results specify that a large
recovery takes place during the first annealing times. Moreover, MET
investigations show nucleation of grains which orientations are found in the
recrystallized texture. The EBSD measurements established that, after
7min30s at 473 K, the microstructure is equiaxed and stable with an average
grain size of about 2 μm.
42.
Etter, A. L., T. Baudin, et al. (2002). "Influence of the Goss grain
environment during secondary recrystallisation of conventional grain
oriented Fe-3%Si steels." Scripta Materialia 47(11): 725-730.
Abnormal Goss grain growth in a conventional grain oriented Fe–3%Si
steel is analysed using orientation imaging microscopy after several
annealing times. Misorientation of boundaries surrounding the growing Goss
grains is characterised. It appears that boundaries misoriented by
20–45° are not specially mobile during the secondary
recrystallisation.
43.
Etter, A. L., T. Baudin, et al. (2002). Influence of the Goss Grain
Neighbourhood during Secondary Recrystallization of Fe-3%Si Sheets. ICOTOM
13, Seoul, Korea, Trans Tech Publications Inc.
Abnormal Goss grain growth in a conventional grain oriented (CGO) Fe-3%Si
electrical steel is analyzed using OIMTM (Orientation Imaging
Microscopy) after several annealing times. Misorientation of grain
boundaries surrounding the growing Goss grains are characterized. In these
conditions, it appears that the two main theories, based on coincident Site
Lattice (CSL) bundaries or high energy (HE) boundaries misoriented by 20 -
45°, cannot be applied to explain the difference of boundary migration
rate during the second recrystallization.
44.
Etter, A. L., T. Baudin, et al. (2006). "Microstructural and textural
characterization of copper processed by ECAE." Materials
Characterization 56(1): 19-25.
A submicron grain (SMG) microstructure, with an average grain size of about
0.4 μm was produced by equal channel angular extrusion (ECAE). Samples
were examined at various scales using the transmission electron microscope
(TEM), the scanning electron microscope (SEM) and the field emission gun
(FEG/SEM) with electron-backscattered diffraction (EBSD) and also the
neutron diffraction. After 8 passes into the channel, which corresponds to a
total strain of about 8, the SMG microstructure was composed of large
dynamic recrystallized grains within a poorly recovered matrix. A
quantitative study of microstructural parameters, such as average low and
high boundary spacings, grain and subgrain aspect ratios and
crystallographic orientations, shows in particular that the area fraction of
low angle boundaries is still very high (60%) and as a consequence the
microstructure is not a true submicron grain structure required to resist
recrystallization during annealing. Indeed, annealing at 200 °C in oil
leads to a stable but not submicron structure, with a grain size of about 2
μm.
45.
Evans, W. J., J. P. Jones, et al. (2005). "Texture effects under
tension and torsion loading conditions in titanium alloys."
International Journal of Fatigue 27(10-12): 1244-1250.
The paper derives from a major research programme on texture evolution and
characterisation in the titanium alloys Ti-6Al-4V and Ti550. The present
publication focuses on the mechanical characterisation of the texture in
rolled plate. It focuses specifically on monotonic strengths and strain
control fatigue under tension and torsion loading. Dependencies of fatigue
performance on specimen orientation are interpreted through EBSD evaluation
of basal and prism plane intensities within the present materials. The
cyclic deformation and mechanisms of failure are related to the relative
magnitude of tensile and shear stress components in the tension and torsion
loading modes. Stress relaxation is shown to play an important part in these
processes. Its relationship to available slip systems is discussed.
46.
Ezawa, H., M. Seto, et al. (2004). Pb-free bumping for high-performance
SoCs. 2004 Proceedings. 54th Electronic Components and Technology
Conference, Las Vegas, Nevada, USA, IEEE.
We have already developed the eutectic Sn-Ag solder bumping process by
alloying Ag/Sn electroplated metal stacks. Alloying electroplated Ag/Cu/Sn
stacks has been also a successful process for Sn-Ag-Cu ternary alloy solder
bumps, confirmed by characterizing melting temperatures and crystallographic
phases. For high-performance system-on-chips (SoCs), the reliability problem
of flip chip solder joints is extending from thermal fatigue failure to
electromigration failure. As the dimensions of solder bumps shrink, the
effects of voids in bumps and crystallographic texture of solder alloys on
electromigration resistance must be discussed as well as current crowding.
In this work, degassing from Ag/Sn stack-plated bumps has been investigated
by thermogravimetry-gas-chromatography/mass-spectrometry (TG-GC/MS). In
addition, the texture of electroplated Ag/Sn metal stacks after reflow under
different cooling conditions has been characterized by electron backscatter
diffraction (EBSD). The experimental results of the gas analyses suggest
that the stack-plating process has potentially an advantage of reduction of
voids in bumps because of the small amounts of evolved gases from the
stacks-plated bumps in comparison with the alloy-plated bumps. From the EBSD
results, the Ag/Sn stack as plated has highly (110) oriented beta -Sn grains
nearly parallel to the substrate surface. Under the reflow condition with a
cooling rate of 200 degrees C/min, the fraction of (110) oriented grains at
around 50 degrees angular tilts toward the substrate increases. As the
cooling rate of the reflow process is reduced to 50 degrees C/min, the
strength of the closest-packed (100) texture of beta -Sn parallel to the
substrate surface increases.
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