Quantitative evaluation of local strain distribution induced by deformation twins and triggering effect of deformation twinning on neighboring grains in polycrystalline AZ31 magnesium alloys

Abstract

$\left\{10\bar{1}2\right\}\text{<}\bar{1}011\text{>}$ deformation twinning commonly occurs in Mg/Mg alloys. In their polycrystals, however, twinning is not always activated at locations with high Schmid factor for $\left\{10\bar{1}2\right\}\text{<}\bar{1}011\text{>}$ twinning. It is believed that twinning behavior in polycrystalline Mg/Mg alloys can be understood with a consideration of interaction between adjacent twins as well as local deformation behavior on a micro- and meso‑structural scale. In this study, we theoretically estimate local plastic strain within twins by transforming coordinates and then compare it with that experimentally obtained from digital image correlation (DIC) analysis for understanding the reason for non-Schmid twinning in polycrystalline-Mg alloys. The theoretically estimated strain of twins was found to be in good agreement with the DIC-strain value. Furthermore, it was observed that the variant selection of twin can be explained by the compatibility parameter m’, rather than Schmid factor, suggesting that twin activation in polycrystalline-Mg is strongly influenced by adjacently appeared twins.