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

Alkorta, Jon [University of Navarra, Spain] Marteleur, Matthieu [UCL] Jacques, Pascal [UCL]

Conventional HR-EBSD is attracting much interest due to its ability of measuring relative crystal misori- entations and microstresses with great accuracy. However, this technique needs the use of simulated pat- terns in order to get absolute values of crystal orientation and stresses and thus expand its use to inter- granular 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 pre- sented 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.