铸态AZ80镁合金高温热变形行为研究

在Gleeble-1500热模拟机上对铸态AZ80镁合金在应变速率为0.005s-1~5s-1、变形温度为200℃~400℃条件下的高温热压缩变形行为进行了研究。结果表明,材料真应力-真应变曲线呈现动态再结晶特征。在温度T≥250℃,试样流变应力行为对应变速率敏感;在低温下T=200℃,应变速率对流变应力影响不大。高温下试样流变应力符合幂指数函数关系,应力指数n为6,热变形激活能Q为220kJ/mol。在高应变速率条件下,试样在变形中的温升是应变量的函数。实验中,Zener-Hollomon参数值大的试样温升明显,而Zener-Hollomon值小的试样变形温度基本保持不变。

Hot deformation behaviors of as-cast AZ80 Magnesium alloy at elevated temperatures

Hot compression tests of as-cast AZ80 Magnesium alloy were performed on Gleeble 1500 at strain rates ranged between 0.005s~(-1)~5s~(-1)and deformation temperature 200℃~400℃.The results show that flow stress behavior is characteristic for hot working processes where DRX leads to work softening and strongly depends on the strain rate during high deformation temperatures(T≥250℃)except low temperature(T=210℃).The relationships between flow stress and deformation temperature as well as strain rate can be represented by the exponential equation during deformation temperature over 200℃.The hot deformation activation energy Q derived from the experimental dates is 220 kJ/mol with stress exponent n=6.The temperature rise caused by deformation at high strain rate is a function of strain and significant when Zener-Hollomon parameter is high.