Observation of {1121} twinning in a Mg-based alloy

The magnesium alloy Mg-5%Y-2%Nd-2%RE-0.5Zr, known as WE54, was heat treated to produce different particle dispersions. Specimens were then compressed to a strain of 8%, and this resulted in prolific mechanical twinning. EBSD analysis revealed that {1121} twins were operative in this alloy, a twinning mode not reported before in magnesium alloys. Activation of this twinning mode is ascribed to the presence of alloying elements in solution. Removal of alloying elements from solution by precipitation treatments completely inhibited this twin mode.