Improving the room temperature stretch formability of a Mg alloy thin sheet by pre-twinning

{10−12} tensile twins were introduced by in-plane compression in a thin magnesium alloy sheet in order to tailor the texture. The room temperature stretch formability of the pre-twinned Mg alloy sheet was remarkably improved (50%). The activation of the tensile twinning in the pre-twinned region, which can effectively accommodate the through-thickness strain during stretch forming, is assumed to be the main reason of stretch formability improvement. Numerical simulation results demonstrate that multidirectional tensile twins induced by multi-steps compression are more beneficial to improve the formability of Mg alloy sheet, compared with uni-directional twins.