摘要

To study the anisotropy of magnesium alloy under dynamic loading condition, the dynamic compression tests of cylindrical ZK61M magnesium alloy specimens in different sampling directions were carried out under high strain rate using split Hopkinson pressure bar. The stress-strain curves of alloy at different strain rates were obtained, and the microstructure after dynamic compression was observed by metallographic microscope. The results show that the number of twins tends to increase with the increase of strain rate for the specimens in the direction of 0° and 45° within the strain rate ranges of 716 s-1 to 1500 s-1. The strain hardening degree is large, which indicates a positive strain strengthening effect. When the strain rate is 739 s-1, the deformation mode for the specimen in the direction of 90° is mainly controlled by twining, but with the increase of strain rate, the number of twins tends to decrease. The dynamic compression property of ZK61M magnesium alloy sheet has obvious anisotropy. The shear sensitivity of the sample is the strongest in the 45° direction between the compression direction and sheet normal direction and the weakest in the 90° direction.