A procedure to obtain correlation curve between local misorientation and plastic strain

Abstract

Numerous studies have assessed the degree of plastic strain induced in polycrystalline materials using crystal orientation mapping data obtained by electron backscatter diffraction. However, it was pointed out that the local misorientation, defined as the averaged misorientation between adjacent measurement points, was difficult to use for a quantitative assessment because the magnitude of the local misorientation was affected by various measurement conditions including the step size, that is the spacing of the crystal orientation measurement points. To quantitatively assess the local misorientation, this study proposed a procedure for estimating the correlation curve between the local misorientation and the degree of plastic strain, which is referred to as the master curve. The procedure to determine the master curve was proposed using Type 316 stainless steel specimens of various degrees of plastic strain. The procedure was based on the characteristics of the change in the misorientation parameters due to the measurement conditions that were investigated using the crystal orientations obtained for various conditions and specimens. It was shown that similar local plastic strain distributions were obtained regardless of the measurement conditions, including especially the step size. From the findings, it was recommended that a smoothing filter should be applied when making a quantitative assessment of the local misorientation.