The mechanism of twinning activation and variant selection in magnesium alloys dominated by slip deformation

Abstract

This study aims to understand the mechanism for activation and variant selection of twinning and the relationship between slip and twinning in Mg alloys. A hot-rolled AZ31 alloy was used for the starting material. The behaviors of basal slip and {10-12} extension twinning (ET) were studied by slip band and electron backscatter diffraction (EBSD) analyses. It showed that the impingement of basal slip on grain boundaries (GBs) in one grain would stimulate ET in the neighboring grain of one soft-soft grain pair. To assess the effect of slip activity on the selection of twin variant, a geometric compatibility factor (m′) between slip and twin was employed. The results showed that the variant of ET was likely activated when it had m′ larger than 0.5 and the 1st or 2nd rank with respect to the impinging basal slip.