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本文运用宏观和微观研究相结合的方法,对国产航空铸镁合金ZM5-T4在应变率为10~(-6)-10~3/s范围作了轴向准静态和冲击压缩试验研究。结果表明:在室温下该材料的应变率敏感性与铸态组织缺陷所引起的试验数据分散性相比是可忽略的。同时还观察到随塑性变形所发展的微裂纹有随应变率增高而增多的倾向。这种与微裂纹演化发展相关的“应变率弱化”效应有可能是抵消位错运动的应变率强化效应而导致综合应变率敏感性降低的主要原因。
In this paper, a combination of macroscopic and microscopic methods was used to investigate the axial quasi-static and impact compression tests of the domestic aviation cast magnesium alloy ZM5-T4 at a strain rate of 10 -6 -6 -10 -3 / s. The results show that the strain rate sensitivity of the material at room temperature is negligible compared to the dispersibility of test data caused by as-cast microstructure defects. It is also observed that the microcracks developed with plastic deformation tend to increase with increasing strain rate. This “strain rate weakening” effect associated with the development of microcracks may be the main reason for offsetting the strain rate hardening effect of dislocation motion and resulting in a decrease in overall strain rate sensitivity.