(1. 中南大学 材料科学与工程学院，长沙 410083；2. 北京航空航天大学 材料科学与工程学院, 北京100083；3. 华中科技大学 材料科学与工程学院，武汉430074)
摘 要: 用Gleeble−1500热/力模拟机研究Mg-9Y-3Zn-0.5Zr镁合金在应变速率为0.001~0.1 /s，变形温度为543~743 K下的热变形行为，分析实验合金在高温变形时的流变应力和应变速率及温度之间的关系，计算变形激活能和应力指数，并讨论热压缩过程中的组织变化。结果表明：在同一变形温度下，实验合金的真应力水平随应变速率的增加而增加，随温度的提高而降低且表现出明显的再结晶特征。当变形温度在643~693 K时，激活能变化不大；当温度大于693 K时，激活能随温度升高而增大。当温度达到693 K时，合金发生了完全再结晶。Mg-9Y-3Zn-0.5Zr合金在693 K挤压后的抗拉强度为340.0 MPa，伸长率为16.2%；该合金在时效后的抗拉强度为396.4 MPa，伸长率为6%, 时效抗拉强度明显上升。
关键字: 镁合金；Y；动态再结晶；热变形
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China; 2. School of Materials Science and Engineering, Beihang University, Beijing 100083, China; 3. School of Materials Science and Engineering, Huazhong University of Science and Technology,Wuhan 430074, China）
Abstract:The thermal deformation behavior of Mg-9Y-3Zn-0.5Zr magnesium alloy at the strain rates of 0.001−0.1 /s and in a temperature range from 543 K to 743 K performed on Gleeble−1500 hot simulator was studied. The results show that the true stress increases with increasing the stain rate at the same temperature, and decreases with increasing the temperature at the same strain rate with a characteristic of dynamic recrystallization. The deformation activation energy increases when the deformation temperature is over 693 K, and it is stable in the range of 643−693 K. The alloy exhibits a complete recrystallization at 693 K, the extruded alloy has a tensile strength of 340.0 MPa and an elongation of 16.2%, and after aging, the tensile strength is 396.4 MPa, the elongation is 6%.
Key words: magnesium alloy; Y; dynamic crystallization; hot deformation
