Tensile twin evolution of Mg–3Al–1Zn magnesium alloy during high-strain rate deformation

Abstract

In order to investigate the evolution of tensile twin in Mg–3Al–1Zn (AZ31) magnesium alloy under high-strain rate impaction, the cylindrical specimens were compressed along the rolling direction under the strain rate of 1600 s−1 by use of split Hopkinson pressure bars equipped with stop rings with different thicknesses. The microstructure was observed by electron back-scatter diffraction. The results show that tensile twinning dominates the early plastic deformation and the area fraction of tensile twins is increased with the increase of deformation strain. Furthermore, when the deformation strain is beyond ∼10%, plastic deformation is mainly dominated by dislocation slips. In addition, most of tensile twins activated in a single grain belong to a variant or a variant pair, which has the highest Schmid factor among all the variants.