高强可焊2195铝-锂合金热压缩变形的流变应力

Flow stress of high-strength weldable 2195 aluminium-lithium alloy during hot compression deformation

在Gleeble 15 0 0热模拟实验机上 ,采用高温等温压缩 ,0 .0 0 1～ 10s-1,变形温度为 36 0～ 5 2 0℃ ,对2 195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 1s-1(变形温度为 5 2 0℃ )和应变速率为 0 .1、0 .0 1、0 .0 0 1s-1(变形温度为 36 0～ 5 2 0℃ )时 ,2 195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 2 195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 .5 6 9× 10 17s-1、0 .0 12 4 8MPa-1和 5 .94 ;热变形激活能Q为 2 5 0 .4 5kJ/mol。

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)(360520 ℃), 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 2.569×10^(17)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.