Hot compression behavior and deformation microstructure of Mg-6Zn-1Al-0.3Mn magnesium alloy

Mg-6Zn-1Al-0.3Mn镁合金的热压缩变形行为及变形组织(英文)

The hot compression behavior of a wrought Mg-6Zn-1Al-0.3Mn magnesium alloy was investigated using Gleeble test at 200-400 °C with strain rates ranging from 0.01 to 7 s-1. The true stress-strain curves show that the hot deformation behavior significantly depends on the deformation temperature and strain rate. The calculated hot deformation activation energy Q is 166 kJ/mol with a stress exponent n=5.99, and the constitutive equation is deduced to be ε＆ =3.16×1013[sinh（0.010σ）]5.99exp [-1.66×105/（RT）]· Deformation microstructure shows that the incompletely dynamically recrystallized grains can be found at grain boundaries and twins with the strain rates ranging from 0.01 to 1 s^-1 at 250 °C, and completely dynamic recrystallization occurs when the temperature is 350 °C or above during hot compression, the size of recrystallized grains decreases with the increment of the strain rate at the same temperature. The relatively suitable deformation condition is considered temperature 330-400 °C and strain rate of 0.01-0.03 s-1, and temperature of 350 °C and strain rate of 1 s-1.

采用Gleeble热模拟方法研究Mg-6Zn-1Al-0.3Mn 变形镁合金在温度为200-400°C，应变速率为0.01-7 s-1条件下的热压缩变形行为。结果表明，变形温度和应变速率显著影响其热变形行为。通过计算获得了热变形激活能及应力指数分别为Q=166 kJ/mol，n=5.99，且其本构方程为ε＆=3.16×1013[sinh（0.010σ）]5.99exp [-1.66×105/（RT）]。热压缩显微组织观察表明：在应变速率为0.01-1 s-1的条件下，在250°C热压缩变形时初始晶粒晶界及孪晶处发生了部分动态再结晶，而在高温（350-400°C）条件下，发生了完全动态再结晶且再结晶晶粒尺寸随着应变速率的增加而减小。获得的较优的变形条件为温度330-400°C、应变速率为0.01-0.03 s-1以及350°C、应变速率为1 s-1。