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The angular resolution of electron backscatter diffraction (EBSD) measurements can be significantly improved using an analysis based on determination of small shifts in features from one pattern to the next using cross-correlation functions. Using pattern shift measurements at many regions of the pattern, errors in the best fit strain and rotation tensors can be reduced. The authors show that elements of the strain tensor and small misorientations can be measured to ±10 -4 and ±0.006° for rotations. We apply the technique to two quite different materials systems. First, we determine the elastic strain distribution near the interface in a cross-sectioned SiGe epilayer, Si substrate semiconductor heterostructure. The plane stress boundary conditions at the sample surface are used to separate every term in the strain tensor. Second, the applicability to structural materials is illustrated by determining the lattice curvature caused by dislocations within the plastic zone associated with the wake and tip of a fatigue crack in a Ni based superalloy. The lattice curvatures are used to calculate the geometrically necessary dislocation content in the plastic zone. © 2006 Institute of Materials, Minerals and Mining.

International audience; This comment on the paper "Bragg's Law diffraction simulations for electron backscatter diffraction analysis" by Kacher et al. explains the limitations in determining elastic strains using synthetic EBSD patterns. Of particular importance are those due to the accuracy of determination of the EBSD geometry projection parameters. Additional references and supporting information are provided.

In this chapter we review the progress that has been made toward elastic strain (i.e., stress) mapping using electron backscatter diffraction. In particular we focus on development of an analysis method based on using cross-correlation to determine small shifts in the EBSD patterns with respect to a reference pattern. The pattern shifts are determined at many subregions dispersed across the wide angular span of the EBSD pattern, and the magnitude and angular distribution of shifts allows the strain and rotation tensor to be determined. Pattern shifts at a resolution of ±0.05 pixels, or in some cases even better, have been reported, which corresponds to a sensitivity of ∼±10-4 in the components of the strain and rotation tensor. © Springer Science+Business Media, LLC 2009. All rights reserved.

In this paper, we describe the use of electron back scatter diffraction (EBSD) to study strain variations in crystalline samples at the nanoscale. The analysis relies on cross correlation measurements of small shifts in the EBSD pattern measured at many points dispersed across the pattern. The method allows the full strain tensor, and lattice rotations to be obtained at a sensitivity of ∼10 -4. The method is applied to study variations of strains and rotations near the surface of 200 nm thick epitaxial layers of Si 0.85Ge 0.15 grown on a Si substrate patterned with rectangular and square mesa. Linescans across rectangular mesas show that strain relaxation and accompanying lattice rotations are restricted to the edges of wide mesas but that the relaxation extends across the entirety of mesas narrower than ∼6 μm. Two dimensional maps of the strain variation in a ∼3 μm wide square mesa are also presented. © 2008 Elsevier Ltd. All rights reserved.