Rotation axes analysis of deformed magnesium based on rotation contour contrast in a scanning electron microscope

Abstract

A crystallographic orientation contrast in the form of cross-shaped and intersecting contours was observed in a backscattered electron (BSE) micrograph of deformed magnesium (Mg) grains in a cold field emission scanning electron microscope (CFE-SEM). This contrast was identified as rotation contour contrast (RCC). A model is presented to link the RCC in the BSE micrograph to the channeling contrast in the corresponding channeling pattern. Based on this model, the appearance of the cross-shaped RCC in the BSE micrograph was attributed to the rotation of the crystal about two rotation axes and the RCC was related to a two dimensional angular scan of the corresponding channeling pattern. This model was experimentally validated using the selected area channeling pattern (SACP) technique. The crystallographic directions of the rotation axes were identified using the electron backscatter diffraction (EBSD) technique.