铝合金多道次热变形过程的动态与静态软化

Dynamic and Static Softening Behaviors During Multistage Hot Deformation of Aluminum Alloys

在Gleeble1500热力模拟机上,采用双道次间隙式等温热压缩试验,对1050、5182和7075铝合金多道次热变形过程中动态与静态软化特性进行研究,变形温度为300℃和400℃,应变速率为0.5s-1,两道次间隙时间在30～120s内变化,每道次应变控制在0.4。结果表明:在400℃时,1050和7075铝合金流动应力由于结构软化而存在相当强的动态软化和奇异的静态软化,导致第二道次的起始流动应力比前一道次的起始流动应力低;对于所有合金,静态软化随着变形温度和道次间保温及停留时间的增加而增加;但是在同一变形条件下,5182铝合金的静态软化速率比1050和7075铝合金高。

The dynamic and static softening behaviors during multistage hot deformation of aluminum alloys (1050, 5182 and 7075 alloy) have been studied by isothermal interrupted hot compression tests in 300℃ and 400℃ at strain rate of 0.5 s-1 on Gleeble 1500. The interrupted deformations were conducted with delay times varying between 30 to 120s after achieving a strain of approximately 0.4 in the first stage. It was indicated that the considerable dynamic softening and exceptional softening associate with a structure softening exist in both 1050 and 7075 alloy deformation at 400℃, leading to the initial flow stress value at the second deformation is lower than that at the first deformation . For all studied alloys, the static softening increases with increasing deformation temperature and holding temperature and delay times, but the increment for 5182 alloy is much higher than that for both 1050 and 7075 alloy in the same hot deformation conditions. 