Mg-10Gd-2Y-0.6Zr合金热压缩变形及其微观组织研究

Study on Hot Compression Deformation of Mg-10Gd-2Y-0.6Zr Alloy and its Microstructure

采用GLEEBLE-1500热模拟机对Mg-10Gd-2Y-0.6Zr合金在温度为350～450℃,变形速率为0.001～0.5s-1,最大变形程度为50%的条件下,进行了恒应变速率高温压缩模拟试验研究,分析了合金高温变形时流变应力与应变速率及变形温度之间的关系以及组织变化。结果表明:合金的稳态流变应力随应变速率的增大而增大,随温度的升高而降低;在给定的变形条件下,计算出合金的变形激活能和应力指数分别为223kJ/mol和6.9,建立了合金高温变形的本构方程;根据试验分析,合金变形温度为400℃,变形速率为0.5s-1,或变形温度为450℃,变形速率为0.1s-1下进行热压缩,可以得到组织结构均匀和热塑性加工良好的匹配。

By GLEEBLE-1500 thermal simulator, high temperature compression simulation experiments of Mg-10Gd-2Y- 0. 6Zr alloy with constant strain rate were studied, which were under the conditions of 350-450 ℃, 0. 001 -0. 5 s^-1 and maxi real deformation of 50%. The microstructure transformation, the relationships between rheological stress and strain rate and temperature, were analyzed under hot deformation. The results showed that the steady-state rheological stress increased with strain rate increasing or deformation temperature decreasing. In given deformation condition, the deformation activation energy and stress index were 223 kJ /mol and 6.9 separately. And the constitutive equation of Mg-10Gd-2Y-0.6Zr alloy was established. A match of good thermoplastic processing and uniform microstructure could be obtained under hot compression with the strain rate of 0.5 s^-1 at 400℃, or with the strain rate of 0.1 s^-1 at 450 ℃.