Application of the pattern matching approach for EBSD calibration and orientation mapping, utilising dynamical EBSP simulations

Abstract

In this paper an alternative method of off-line Kikuchi pattern centre calibration and orientation mapping, utilising the cross-correlation between entire experimental patterns and dynamical simulated patterns is applied and evaluated. To demonstrate the improvement in angular resolution compared to Hough transform based methods, EBSD datasets of a silicon monocrystal were analysed using both, classical and the presented cross-correlation based method, which revealed significant enhancement of angular resolution for the refined method. The mean misorientation over the monocrystalline sample was found to be up to one order of magnitude lower compared to common methods, with an angular resolution of up to 0.06° indicating a substantial gain in orientation precision. The pattern centres were determined for a number of patterns on the map, using pattern matching refinement as well. Subsequently, a multiple linear regression model was computed to correlate pattern centre positions (XPC, YPC) and detector distances (ZSSD) to x- and y-coordinates on the map by means of plane equations. Employing this method, a reduction of orientation noise was achieved in highly deformed Silicon crystals with large intragranular orientation ranges. Furthermore, it was shown that the cross correlation coefficient CC can be used as a parameter indicating the pattern quality and hence can be utilised to create a pseudo greyscale image of the surface, showing grain boundaries and also depicting lattice distortions.