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研究了挤压态AZ31镁合金在压缩过程中的组织变化及其演变机制,探讨了孪生对加工硬化的影响。结果表明,当应变量小于4%时,孪晶含量随应变增大而增多;此后,随应变增加,孪晶含量反而逐渐减少,显微组织分析表明发生了退孪生现象。但织构分析表明,镁合金在压缩过程中并没有发生退孪生。孪晶长大与合并模型被用于解释组织分析显示的孪晶产生和消失现象。在挤压态镁合金的压缩过程中,孪晶的长大与合并导致基体几乎被消耗完毕,大部分基体转变成了孪晶组织,孪晶合并成片,以至于在显微组织观察中产生了孪生先产生后消失的假象。研究还表明,在孪生过程中镁合金的晶体取向发生86.3°的转变,使得镁合金从软取向变成了硬取向,这种取向的转变是镁合金压缩变形过程加工硬化的主要原因。
The microstructure and the evolution mechanism of the as-extruded AZ31 magnesium alloy during compression were studied, and the effect of twinning on work-hardening was also discussed. The results show that when the amount of strain is less than 4%, the content of twins increases with the increase of strain. After that, the amount of twins decreases with the increase of strain, and microstructure analysis shows that the twinning occurs. However, the texture analysis shows that the magnesium alloy does not occur during the compression process back-twins. Twin growth and merger models were used to account for the generation and disappearance of twins as revealed by tissue analysis. In the squeeze state of magnesium alloy compression process, the twins grow up with the merger led to the matrix is almost consumed, most of the matrix into twins, twins merged into pieces, so that the microstructure observation The illusion that the twins first disappeared. The study also shows that the crystal orientation of the magnesium alloy changes by 86.3 ° in the twin process, which leads the magnesium alloy to change from a soft orientation to a hard orientation. This orientation change is the main reason for the work hardening of the magnesium alloy during the compressive deformation process.