Influence of local strain on twinning behavior during compression of AZ31 magnesium alloy

The effect of local strain state on twinning behavior during compression of AZ31 magnesium alloy was investigated, making use of a micro-grid method to correlate the local strain tensor with observations of twinning using electron backscatter diffraction (EBSD) measurements. Eight prism samples were used to get deformation zones subjected to different strain states. The strain distribution across the whole sample surface was measured with the micro-grid method and the results show that the local strain states exhibit much variation, with zones subjected to large shear strain as well as zones subjected to little shear strain. Samples were compressed at room temperature and detailed EBSD measurements were taken in two zones, where one zone was subject to only small shear strains and the other was subject to large shear strains. Twin variant selection was then analyzed with respect to both stress-based (Schmid factor) and strain-based criteria. The former was found to provide the best explanation for the observed pattern of twinning. (C) 2015 Elsevier B.V. All rights reserved.