{1012}拉伸孪晶对AZ31B镁合金动态力学行为及应变速率敏感性的影响
Effect of {1012}Tension Twining on Dynamic Mechanical Behavior and Strain Rate Sensitivity of AZ31B Magnesium Alloy
王长义1,2, 刘 正1, 毛萍莉1
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作者单位：1. 沈阳工业大学 材料科学与工程学院, 辽宁 沈阳 110870; 2. 辽宁装备制造职业技术学院 实习实训中心, 辽宁 沈阳 110161)
中文关键字：镁合金； 孪生； 织构； 应变速率敏感性
英文关键字：magnesium alloy; twining; texture; strain rate sensitivity
中文摘要：采用分离式Hopkinson压杆和反射式拉杆装置在室温对挤压态AZ31B镁合金进行了动态压缩和拉伸试验，分析了AZ31B镁合金沿挤压方向压缩和拉伸时的不对称性和应变速率敏感性。 结果表明：沿挤压方向压缩时，拉伸孪晶{1012}<1120>首先启动，屈服强度对应变速率不敏感；沿挤压方向拉伸时，拉伸孪晶不能启动，位错滑移参与变形，应变速率敏感性有所提高；由于拉伸孪晶只能单向启动，AZ31B镁合金在挤压方向的动态拉压不对称性显著。
英文摘要：Dynamic compression and tension tests of extruded AZ31B magnesium alloy were carried out using a split Hopkinson pressure bar and a reflected hopkinson tension bar apparatus at room temperature. Tension-compression asymmetry and strain rate sensitivity of AZ31B magnesium alloy were analyzed when tested along extruding direction. The results show that when the alloy is compressed along extruding direction,{1012}<1120> tension twining is initiated first, resulting that the yield stress of the alloy is insensitive to strain rate. When the alloy is tested in tension along extruding direction, {1012}<1120> tension twining is not initiated, but dislocation slip is responsible for the plastic deformation, resulting that strain rate sensitivity grows. Because of the polarity of tension twining, the tension-compression asymmetry of AZ31B magnesium alloy is much pronounced when tested along extruding direction.