ZK31+0.3Yb镁合金的热力模拟

Thermal mechanical simulation of ZK31+0.3Yb magnesium alloy

通过热压缩变形实验,利用光学显微镜观察,对ZK31+0.3Yb镁合金变形过程的流变应力和组织演变进行研究。研究结果表明663K/0.1s-1是最佳的变形条件,在此条件下,合金的流变应力低,动态再结晶充分激发,合金的塑性好;当变形温度降至623K和573K时,动态再结晶不能充分激发,合金变形的流变应力明显提高,尤其是573K变形时流变应力达到185MPa;而变形温度提高到723K时,晶界处形成楔形裂纹,合金的塑性差;在663K时变形,尽管应变速率降低至0.001s-1,合金的动态再结晶充分激发,流变应力下降,但变形的进程被减缓;当变速率提高到1.000s-1时,晶粒间的协调变形不能发挥作用,合金的塑性最差。

The flow stress and microstructure evolution of ZK31 ＋0. 3Yb magnesium alloy were studied through hot compression deformation experiment and optical microscope observation. The results show that the suitable deformation condition is 663 K/0.1 s^-1 , which results in low flow stress and that the good ductility of the alloy is obtained due to the activation of dynamic recrystallization（DRX） of the alloy. When the temperature is decreased to 573 K and 623 K, the flow stress increases obviously due to the inhibited of the DRX, especially, the flow stress increases to 185 MPa when the temperature decreases to 573 K. The wedge cracking initiates at the grain boundary when the temperature increases to 723 K, which causes the poor ductility of the alloy. Although strain rate is decreased to 0. 001 s^-1 , which causes the low stress due to DRX activated sufficiently, the deformation process is slowed down. Increasing the strain rate to 1. 000 s^-1 causes the poorest ductility due to the fracture of compatible deformation between grains.