Effect of grain size on the microstructure and deformation mechanism of Mg-2Y-0.6Nd-0.6Zr alloy at a high strain rate

Abstract The dynamic mechanical behaviour of Mg-2Y-0.6Nd-0.6Zr alloys with different grain sizes at a high strain rate (1100 s-1) was investigated in this study, and the effect of grain size on the microstructure and deformation mechanism was analysed. In the process of dynamic compression, fine grains (3 μm) can inhibit the formation of twinning, the majority of twins in coarse grains are {10 1 ( — ) 2} tensile twins, and the number of {10 1 ( — ) 2} tensile twins increases with increasing grain size. The accumulation of dislocations is more obvious in fine grains. Under dynamic conditions, dislocations more easily move in the samples with smaller grain sizes. With increasing grain size, the main deformation mechanism change from dislocation and dislocation slip to {10 1 ( — ) 2} tensile twin and dislocation slip.