Plastic deformation mechanisms of AZ31 magnesium alloy under high strain rate compression

The twinning and slip activities of AZ31 magnesium alloy sheet at a strain rate of 1 200 s^-1 were investigated. Dynamically mechanical properties of various oriented samples were measured using Split Hopkinson Pressure Bar(SHPB). Optical microscope observations reveal that the dominant deformation mechanism is twinning for 90° oriented sample, and is slip for 45° and 0° oriented samples. TEM analysis for samples at a strain of 0.3% shows that the main deformation mechanisms for 90°, 45° and 0° oriented sample are {10{A figure is presented}2} < 10{A figure is presented}1 > and {10{A figure is presented}1} < 10{A figure is presented}2 > twinning, basal slip and non basal slip, respectively. The main features of the true stress-true strain curves can be explained based on deformation mechanism analysis.