Accuracy assessment of elastic strain measurement by EBSD

Abstract

A detailed accuracy analysis of electron backscatter diffraction (EBSD) elastic strain measurement has been carried out using both simulated and experimental patterns. Strains are determined by measuring shifts between two EBSD patterns (one being the reference) over regions of interest (ROI) using an iterative cross-correlation algorithm. An original minimization procedure over 20 regions of interests gives a unique solution for the eight independent components of the deviatoric displacement gradient tensor. It is shown that this method leads to strain measurements on simulated patterns with an accuracy better than 10(-4). The influence of the projection parameters is also investigated. The accuracy assessment is illustrated by two worked examples: (i) four-point bending of a silicon single crystal and (ii) Si(1-x)Ge(x) layers on a Si substrate. Experimental results are compared with finite-element simulations.