Dynamic compressive behaviour and microstructural evolution of extrusion-shear Mg–6Zn–1Cu–1Y–0.6Zr alloy

Abstract

In this work, the alloy Mg–6Zn–1Cu–1Y–0.6Zr was prepared using an extrusion-shear method, which combines traditional extrusion with the equal channel angular pressing. Dynamic compressive behaviour and microstructural evolution were studied along the extrusion direction with strain rates in the range of 695–1995 s⁻¹ using a Split-Hopkinson pressure bar. The dynamic compression properties have a distinct positive strain rate strengthening effect. A texture transition from ⟨10–10⟩ into ⟨0001⟩ is found in the Mg–6Zn–1Cu–1Y–0.6Zr alloy. Analysis of the microstructural evolution shows that {10–12} extension twinning and (0002) basal-type slip are major deformation mechanisms. The absorption energy density dramatically increases as the strain rate increases, results indicate that dynamic recrystallisation and high yield strength are mainly responsible for the high energy absorption capacity.