Microstructure evolution and characterization of the adiabatic shear bands in AZ31 magnesium alloy

The diffuse adiabatic shear bands (ASBs) of the AZ31 magnesium alloy under high-strain-rate compression are systematically studied. Dynamic compression experiments at a strain rate of 1200 s−1 were conducted using a split Hopkinson pressure bar, and the microstructure of the specimen was characterized via optical microscopy, electron backscatter diffraction, and transmission electron microscopy. The results show that the microstructure after high-strain-rate deformation can be divided into three regions, namely the matrix region, transition region, and ASB region, and the corresponding grain crystal orientations are random, textured, and random, respectively. The microstructure exhibits high-density twins after high-strain-rate deformation. The dynamic recrystallization (DRX) of the ASB region is controlled by the combination of the twinning-induced DRX, continuous DRX, and discontinuous DRX.