Adiabatic shear behaviour of AZ31 alloy with different grain size under high-strain-rate

The effect of grain size on the adiabatic shear behaviour of AZ31 Mg alloy under high-strain-rate deformation was investigated in the present study. Samples with three types of grain sizes were prepared, and the hat-shaped samples were subjected to the high-strain-rate deformation. The high-strain-rate deformation was conducted at 1600 s–1 by using a split Hopkinson pressure bar at 200°C. The microstructure before and after deformation was observed by optical microscopy and electron backscatter diffraction. The results indicated that the adiabatic shear sensitivity increased with the increase in the grain size. The calculation results indicated that the dynamic recrystallisation grains in the adiabatic shear band were formed by rotational dynamic recrystallisation.