中文摘要：

利用Hopkinson压杆试验机和限位环限制技术,并通过显微组织观察等研究了AZ31镁合金在动态冲击下的变形行为和组织演变,最后分析了AZ31镁合金的塑性变形机制。结果表明：在1 524-2 024s^-1的应变速率范围内,AZ31镁合金的流变应力随着应变的增大而逐渐增大,表现出明显的应变强化效应;随着塑性变形的增加,AZ31镁合金塑性变形机制依次为滑移＋孪生、晶粒细化、变形局部化;剪切带内的温升约为241K,达到了孪生动态再结晶的形核温度;晶粒内部的滑移和孪晶转动是剪切带内晶粒细化的主要机制,短暂的温升促进了剪切带内晶粒的细化。

英文摘要：

The deformation behavior and microstructure evolution of AZ31 magnesium alloy at the dynamic impact were studied by Hopkinson pressure bar testing,the spacing ring limit technology and microscopic observation,etc.At last,the plastic deformation mechanisms of AZ31 magnesium alloy were analyzed.The results show that the flow stress of AZ31 magnesium alloy increased with the increase of strain gradually in the range of strain rate from 1 524s^-1 to 2 024s^-1 and demonstrated the strain strengthening effect.The plastic deformation mechanisms of AZ31 magnesium alloy were transformed in turn by the slip and twinning,grain refinement,deformation localization with the increase of plastic deformation.Meanwhile,the temperature within shear band was about 241 Kand met the twinning dynamic recrystallization′s temperature.The slip and twin rotation in grain are the main mechanism of grain refinement within shear bands,and the transient temperature rise promotes the grain refining.