Observation and Schmid factor analysis of multiple twins in a warm-rolled Mg-3Al-1Zn alloy

This study aims to understand the features of twinning that occurred during warm-rolling of Mg-3Al-1Zn alloys. The rolling was performed at 150 °C with the c-axis of most grains nearly parallel to the transverse direction. Electron backscatter diffraction analysis was conducted to examine microstructural evolution of the rolled sample. Multiple twins including {10−12} extension twin, {10−11} contraction twin, {10−11}-{10−12} and {10−12}-{10−11} double twins and {10−12}-{10−11}-{10−12} tertiary twins were observed in the rolled sample. These twins were present even in the same grain orientation. Based on the applied rolling deformation, an effective Schmid factor was calculated to understand the activation of twinning. Calculated Schmid factor maps were obtained as a function of (0001) pole. The activation of {10−12}-{10−11} double twin was explained by the statistical analysis of Schmid factors for primary {10−12} twin and secondary {10−11} twin.