高Zr含量Cu-1.0%Zr-0.15%Y合金高温变形行为

Hot Deformation Behavior of Cu-1.0%Zr-0.15%Y Alloy with High Zr Content

利用Gleeble-1500D热模拟试验机对Cu-1.0%Zr-0.15%Y合金进行等温热压缩实验。分析了合金变形温度为550~900℃,应变速率为0.001~10 s^(-1)条件下的真应力-真应变特征、热压缩过程中的组织演变和热变形机制。结果表明:在550~750℃时具有典型的动态回复特征,在850~900℃时具有动态再结晶热变形特征。变形温度和应变速率对Cu-1.0%Zr-0.15%Y合金有显著影响。在真应力-真应变曲线的基础上,建立等温压缩变形过程中的流变应力与应变速率和变形温度之间的本构方程,得到合金的热变形激活能Q为379.16 kJ/mol,与纯铜相比,高Zr含量Cu-1.0%Zr-0.15%Y合金热变形激活能提高了81%。添加稀土元素Y,可以细化Cu-Zr合金晶粒,促进动态结晶。

The isothermal hot compression test of Cu-1.0%Zr-0.15%Y alloy was carried out using a Gleeble-1500D thermal simulation machine. The characteristics of true stress-true strain, microstructure evolution and hot deformation mechanism of the alloy were investigated at elevated temperature of 550-900 ℃ and at the strain rates of 0.001-10 s-1. The results show that the typical characteristics of dynamic recovery occur at the deformation temperature of 550-750 ℃, while the characteristics of dynamic recrystallization occur at the deformation temperature of 850-900 ℃. The deformation temperature and strain rates have significant effects on the microstructure of Cu-1.0%Zr-0.15%Y alloy. Based on the true stress-strain curves, the constitutive equation of the flow stress and strain rates as well as deformation temperature during isothermal compression deformation is established. The hot deformation activation energy of the Cu-1.0%Zr-0.15%Y alloy is 379.16 kJ/mol, which is increased by 81% compared with that of pure copper. The addition of rare earth element Y not only refines the alloy grains but also promotes the dynamic recrystallization.