Electron Backscatter Diffraction (EBSD)
60% Recrystallized Low Carbon Steel
(Grain Reference Misorientation Map)
Orientation Map of Deformed Steel
Tire Cord
An 8 Slice 3D OIM Scan of a Laves-phase precipitate in a hot rolled Fe3Al-base alloy. The distance between each section is approximately 300 nm.
Duplex Stainless Steel
Retained Austenite
A combined image quality and orientation map from a partially recrystallized steel
EBSD image quality and orientation map of dual phase Ferrite-Martensite steel
Orientation map from dual phase low carbon steel
Orientation map of Twinning Induced Plasticity (TWIP) steel showing twin boundaries introduced during deformation
EBSD image quality map of Dual Phase steel showing duplex microstructure
Leading edge EBSD orientation map
Trailing edge EBSD orientation map
Martensitic steels are used in a wide range of applications and control of the retained austenite is important for both the mechanical properties and service lifetime of the material. This application example studies an inlet guide vane in a gas turbine engine. The vane directs gas flow at the correct angle while controlling mass flow and is subjected to high temperatures and pressures during operation. The figures to the above show orientation maps of leading and training edge regions along the guide vane showing a tempered martensitic structure.
Leading edge phase map showing retained austenite distribution in yellow
Trailing edge phase map showing retained austenite distribution in yellow
The images above show phase maps of these regions with the martensite colored blue and the retained austenite colored yellow. The leading edge region has approximately four percent retained austenite while the trailing edge has approximately two percent, suggesting the leading edge is at a higher risk for failure due to transformation of the retained austenite. The retained austenite within the leading edge analysis area is generally randomly distributed while the trailing edge area has a more segregated distribution with the lower region having more retained austenite than the upper region.
EBSD showing microstructure and twin boundaries present in TWIP steel
High strength steels, aluminum and magnesium alloys are three candidates being explored to meet automotive fuel efficiency targets. One example of advanced engineered steel is Twinning Induced Plasticity (TWIP) steel. TWIP steels are designed to absorb more energy in a crash than traditional steels, while maintaining strength and stability. This property is the result of twinning that occurs during the plastic deformation during a crash, thereby increasing the yield strength of the material. As shown in the image to the left, EBSD is used to measure the microstructure and twin boundaries present in the steel before and after deformation. This information is used to improve and optimize the processing conditions to maximize twin formation during deformation.
EBSD map of a cross-section of an aluminum Friction Stir weld
With a significantly lower density than steel, aluminum offers great potential for weight reduction. Honda has recently announced that the 2013 Accord will feature steel and aluminum components joined using a continuous welding process called friction stir welding. The process enables joining of dissimilar metals with resulting weld strength greater than conventional Metal Inert Gas welding. This new technology reduced body weight by 25% and electricity consumption during welding by 50%. The image above shows an EBSD map of a cross-section of an aluminum Friction Stir weld. EBSD measures the grain size and shape, orientation and plastic deformation from the base metal, the heat affected zone and the center weld nugget. This information provides insight into material flow during the welding process and feedback to optimize welding parameters used to maximize weld quality between different materials.
A combined image quality and orientation map from the Gibeon meteorite
IPF map (left) and FSD image (right) showing deformation structures in steel
IPF map (left) and GS map (right) for BCC iron
Grain size distribution for BCC iron
Sintered Steel
The forward scatter detector (FSD) provides qualitative imaging of deformation structures within grains, as is apparent in sintered steel. There is a significant amount of orientation contrast in the FSD image (left), whereas the SE image (right) illustrates only macroscopic boundaries.
EBSD orientation map from a 3-D printed and sintered 316L stainless steel sample where identified twin boundaries are colored white and random grain boundaries are colored black. Local porosity is also identified as larger black regions within the microstructure.
Ilmenite Sample
- Simultaneously collected Energy Dispersive Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD) using an Octane Elite Silicon Drift Detector and Hikari Super EBSD camera with APEX™ Software
- Data collected from a sample from Saint Urbain Anorthosite Massif in Quebec, Canada
- System contains economic deposits of titanium and iron in Fe/Ti oxide minerals
- Montage functionality in APEX enables large area data collection
- Chi-Scan™ is used to differentiate the crystallographically similar Ilmenite with exsolution lamellae of hematite
- EDAX tools used to measure grain size and shape of each constituent phase
Weak screw (top) and strong screw (bottom)
- Collected with a Velocity™ Super EBSD Analysis System with APEX™ EBSD Software
- Two large Montage maps of cross-sections through the entire screw
- Weak Screw: 67 million points – 700 nm steps; 350 fields
- Strong Screw: 85 million points – 200 nm steps; 157 fields
- All fields collected at 500 x magnification
- Shown: Two colored grain size maps overlaid on PRIAS™ grayscale maps
- The weak screw is prone to breaking when being fastened. The head snaps off when tightening at the first narrowing below the head. The strong screw is durable and does not break.
- The reason for this difference is in the microstructure. The weak screw shows large grains that have been severely deformed in between the threads. When force is applied to the screw, the shaft breaks on one of these narrow, deformed areas. The strong screw has a uniform fine-grained microstructure that does not show such weakness.
Micro X-ray Fluorescence (Micro-XRF)
A large area of this Odessa meteorite section was elementally imaged to elucidate the structure of this extraterrestrial object which impacted the earth some tens of thousands of years ago.
S(K) map: Sulfur in this nodular form is generally associated with Troilite.
Ni(K) map: Shows Ni rich phases of Taenite and Schreibersite interspersed in the major Kamacite phase.
RGB merge: Fe (red), Ni (green), S (blue) showing a nodular Troilite phase (FeS) in purple surrounding a graphite inclusion.
Spectral Comparison of Glass Fragments
Micro-XRF enables spectral comparison of glass fragments from the same windshield. The fragments from the inner and outer laminates of the glass have differences, mainly in Fe content.
A lunar rock composed of transition elements rather than higher energy actinides. The data is represented by elemental maps instead of spectral plots. Starting from the left, these are the results from an uncontained sample, followed by samples contained with 50.8 μm nylon, 50.8 μm Teflon, and 127 μm Teflon containment bagging with analysis done in vacuum. The higher intensity color indicates stronger signal intensity with less signal absorption by the barrier material. Even using the higher density Teflon barrier material in comparison to the nylon, it is possible to efficiently analyze lower energy transition elements with the barrier in place. The goal in this case was to evaluate the impact of using increasingly stronger gas tight containment bags on the elemental analysis via micro-XRF.
Steel spectra with electron (red) and X-ray (black) excitation
Wavelength Dispersive Spectrometry (WDS)
Spectra from a stainless steel sample illustrating the resolution improvements of WDS versus EDS