Mg-Gd-Y-Zr合金热变形本构方程

摘要

Three kinds of constitutive equations, power law (PI), expression law (El) and sine hyperbolic law (SI) were used to analyze the flow behavior of the Mg-6Gd-3 Y-0.5Zr alloy after compression at temperatures of 300-500 °C and strain rates of 10-3-1 s-1 by using Geeble-1500 test machine. The microstructures were studied using scanning electron microscope (SEM). The results show that El fits the experimental results better than PI and SI. And even, the sine hyperbolic law with the optimization of material parameter a (SIO) exhibits the close precision to El. The precipitated heat-resisting phase after compression is the reason for El better fitting than PI and SI.%采用Geeble- 1500热模拟实验机测试了高强耐热Mg-6Gd-3Y-0.5Zr合金在变形温度为300～500℃、应变速率为10-3～1 s-1下的流变力学行为,采用扫描电子显微镜对其微观组织进行观察,分析了幂函数(PI)、指数函数(EI)和双曲正弦函数(SI)半经验本构方程对该合金变形行为拟合的适用性.结果表明:EI拟合实验结果精度大于PI和SI的,即使对SI函数中材料常数α进行一定优化处理得到SIO函数的拟合精度,也与EI函数十分接近.合金中高温耐热相提高合金高温下的强度是EI拟合优于PI和SI的原因.