( 1. 中南大学 材料科学与工程学院,长沙 410083;
2. 西南铝业(集团)有限责任公司,重庆 401326)
摘 要: 在Gleeble-1500热模拟实验机上,采用高温等温压缩,0.001~10 s-1,变形温度为360~520 ℃,对2195铝-锂合金在高温压缩变形中的流变应力行为进行了研究,分析了其高温变形的物理本质。结果表明:在应变速率为1 s-1(变形温度为520 ℃)和应变速率为0.1、0.01、0.001 s-1(变形温度为360~520 ℃)时,2195铝-锂合金热压缩变形流变应力出现了明显的峰值应力,表现为连续动态再结晶特征;在其它变形条件下存在较为明显的稳态流变特征;可采用Zener-Hollomon参数的双曲正弦函数来描述2195铝-锂合金高温变形时的流变应力行为;在获得的流变应力σ解析表达式中,A、α和n值分别为2.569×1017 s-1、0.012 48 MPa-1和5.94;热变形激活能Q为250.45 kJ/mol。
关键字: 2195铝-锂合金;热压缩变形;流变应力;Zener-Hollomon参数
hot compression deformation
( 1. School of Materials Science and Engineering,
Central South University, Changsha 410083, China;
2. Southwest Aluminium (Group) Co. Ltd, Chongqing 401326, China)
Abstract: By isothermal compression test at Gleeble-1500 thermal-mechanical simulator, the flow stress behavior of 2195 aluminium-lithium alloy during hot compression deformation was studied with the strain rate rang from 0.001 s-1 to 10 s-1 and the temperature range from 360 ℃ to 520 ℃. The physical essence of hot deformation for 2195 alloy was also studied. The results show that when the strain rate is 1 s-1(the deformation temperature is 520 ℃) and 0.001, 0.01 and 0.1 s-1(360-520 ℃), the flow stress decreases after a peak value, showing continuous dynamic recrystallization. The steady-state flow characteristics exist on the other deformation conditions. The flow stress of 2195 alloy during high temperature deformation can be expressed by a Zener-Hollomon parameter in the hyperbolic sine function. The values of A, α and n in the analytical expressions of flow stress(σ) are fitted to be 2.569×1017 s-1, 0.012 48 MPa-1 and 5.94. The hot deformation activation energy of 2195 alloy during hot deformation is 250.45 kJ/mol.
Key words: 2195 aluminum-lithium alloy; hot compression deformation; flow stress; Zener-Hollomon parameter