高应变率下AZ31B镁合金力学行为各向异性

Research on the Anisotropy of Hot Rolled AZ31B Alloy at High Strain Rates

摘要:

利用分离式Hopkinson压杆和应变控制技术研究了AZ31B镁合金在压缩受力方向与轧制板面的法向成不同角度时的动态力学特性，同时分析了不同应变量下的塑性变形机制。结果表明：当加载应变率为1200 s-1时，不同取样方向的样品中孪晶数量均随塑性变形应变量的增大而增多；当加载应变率增大到为2800 s-1时，取样方向为0°和45°、流变曲线形状较应变率为1200 s-1时没有明显变化，而取样方向为90°时曲线形状由应变率为1200 s-1时的凹形变为凸形，曲线形状变化的原因是由于应变量增大，热软化效应使得孪

Abstract:

Dynamic compressive performances of hot rolled AZ31B which have different angles between the compressive direction and the normal direction of the rolled sheet were tested using SHPB and strain control techniques. The mechanism of the plastic deformation at different strain amount was studied. Results indicate that when the strain rate is 1200 s-1, the twin number of samples in different orientation increases with plastic strain increasing; when the strain rate increases to 2800 s-1, the σ-ε curves have no obvious charges as the angle is 0o and 45o, compared with that at 1200 s-1; however the σ-ε curves vary from concave to convex when the angle is 90o, because thermal softening has occurred with increasing plastic strain, which results in the number of twin decreasing, and smaller strain hardening