Understanding deformation with high angular resolution electron backscatter diffraction (HR-EBSD)

TL;DR

HR-EBSD significantly enhances angular and strain measurement precision in materials science by using advanced image analysis to detect minute lattice misorientations and strains, enabling detailed deformation analysis.

Contribution

This paper introduces HR-EBSD with improved angular resolution and demonstrates its application to real materials deformation studies.

Findings

Achieved measurement of misorientations as small as 1E-4 radians.

Demonstrated high sensitivity to lattice strains and rotations.

Applied technique to study deformation in polycrystalline alloys.

Abstract

High angular resolution electron backscatter diffraction (HR-EBSD) affords an increase in angular resolution, as compared to 'conventional' Hough transform based EBSD, of two orders of magnitude, enabling measurements of relative misorientations of 1E-4 rads (~ 0.006 {\deg}) and changes in (deviatoric) lattice strain with a precision of 1E-4. This is achieved through direct comparison of two or more diffraction patterns using sophisticated cross-correlation based image analysis routines. Image shifts between zone axes in the two-correlated diffraction pattern are measured with sub-pixel precision and this realises the ability to measure changes in interplanar angles and lattice orientation with a high degree of sensitivity. These shifts are linked to strains and lattice rotations through simple geometry. In this manuscript, we outline the basis of the technique and two case studies that highlight its potential to tackle real materials science challenges, such as deformation patterning in polycrystalline alloys.