Deformation Mechanism And Failure Behavior Of Magnesium Alloy Under High Strain Rate And Quasi-static Loading

Magnesium alloy has been widely used in social production and daily life currently due to its distinguished properties. Many works have been performed on quasi-static deformation behaviors of magnesium alloy thoroughly at home and abroad. But there are few articles relating to the dynamic mechanical properties of magnesium alloy. Therefore it is of great significance to investigate the dynamic mechanical properties of magnesium alloy, in order to solve the problem of vehicle collision. In this study deformation mechanism and failure behavior at high strain rate are analyzed by using Split Hopkinson Pressure Bar (SHPB) and Split Hopkinson Tension Bar (SHTB).Extruded AZ31 was tested in tension (at room temperature and elevated temperature) and compression at high strain rate using Hopkinson bar apparatus. It was also tested in quasi-static tension. In addition waveform shaper was studied. SHPB was used to investigate the dynamic mechanical behavior of extruded AZ31 under load directions (extrusion direction (ED), normal direction (ND) and transverse direction (TD)) at room temperature. The anisotropic effect on dynamic mechanical behavior of extruded AZ31 magnesium alloy under high-speed impact compression was discussed in the meanwhile. The effects of elevated temperature and high strain rates on mechanical behavior were also analyzed. The tensile properties of extruded AZ31 at high strain rates were compared with the quasi-static tensile properties of it. In the paper, waveform shaper was also studied.The results show that along ND and ED extruded AZ31 has remarkable strain hardening effect and along TD extruded AZ31 is not strain-rate sensitivity. With increasing the strain rate, yield strength and maximum magnitude of stress along different direction change variously. ND has the greatest change. On the contrary TD has the least change. Extruded AZ31 is sensitive to strain rate in high-speed impact tension test and quasi-static tension test. Thermal softening effect is responsible for the withdrawal of strain rate strengthening. Furthermore shaper of copper can weaken the dispersion and shaper of transparent tape can help to realize constant strain rate loading.