Improved simulation based HR-EBSD procedure using image gradient based DIC techniques

Conventional HR-EBSD is attracting much interest due to its ability of measuring relative crystal misorientations and microstresses with great accuracy. However, this technique needs the use of simulated patterns in order to get absolute values of crystal orientation and stresses and thus expand its use to intergranular analyses. Simulation-based approaches have shown many limitations due to the poor correlation with the real patterns specially when Bragg simulations are considered. This paper presents an improved algorithm based on gradient-based correlation techniques that makes simulation-based HR-EBSD possible. Based on this new algorithm, a new pattern center calibration procedure is proposed and validated. Also, a new hybrid procedure that combines simulation-based HR-EBSD with conventional HR-EBSD is presented that enables an absolute determination of both orientations and stresses with improved accuracy. The hybrid HR-EBSD is used to analyze the martensitic transformation induced by plastic deformation in an as-quenched Ti-12wt.%Mo alloy.