Dynamic compression behaviour and constitutive description of fine-grain Mg–4Zn–1Y alloy

Abstract

In this research, the dynamic compression behaviour of 5 and 1.5 µm grain size samples of Mg–4Zn–1Y alloy was investigated by the split Hopkinson pressure bar at the strain rate of 1000–1700 s⁻¹. The microstructure, texture evolution, and the deformation mechanisms of samples were characterised by electron backscattering diffraction. The result showed that the grain refinement caused tension twining, which resulted in the distinct true stress–strain curves with specific grain sizes. It was found that the pyramidal < c + a > and pyramidal <a > slips were the main deformation mechanisms of 5 and 1.5 µm samples under dynamic compression, respectively. The constitutive modelling of Mg–4Zn–1Y with different grain sizes was also developed by introducing the grain size adjustment parameters.