Study on the Dynamic Deformation Behavior of Extruded AZ31 Magnesium Alloy with Different Grain Sizes Based on the VPSC Model
摘要
In order to investigate the effects of grain size on the mechanical properties, texture evolution, and deformation mechanisms of extruded AZ31 magnesium alloy under dynamic loading, this study uses a split Hopkinson pressure bar to perform dynamic compression at a strain rate of 1700 s−1 on AZ31 magnesium alloy samples with three different grain sizes (3 μm, 35 μm, and 50 μm) along the ED direction at room temperature. The results show that with an increase in grain size, both the yield stress and peak stress of the magnesium alloy decrease. It was also found that the c-axis orientation of most grains in the samples with three different grain sizes was approximately at a 45° angle to the < 0001 > direction. When the grain size is 3 μm, the primary deformation mechanism is pyramidal < c + a > slip. For the 35 μm and 50 μm samples, the main deformation mechanisms are pyramidal < c + a > slip and {10-12} tensile twinning, and as the grain size increases, the activity of {10-12} tensile twinning increases. As grain size increases, the rising proportion of {10-12} tensile twinning activity suppresses the activation of pyramidal < c + a > slip, thereby reducing the ductility of the magnesium alloy.