2091Al-Li合金两种应变状态超塑成形后时效动力学特点的研究

Studies on Aging Dynamic Characteristics of 2091 Al-Li Alloy after Superplastic Forming at Two Strain States

研究了2091Al－Li合金平面应变状态和体应变状态的超塑性成形后时效动力学特点。结果表明，时效后显微硬度比超塑成形后有很大提高；随着时效时间的增加，显微硬度呈规律变化。其变化与微空洞的消失、空洞体积的减少和微观组织的变化有关。平面应变状态的硬度峰值低于体应变状态的，而且应变量不同时出现硬度峰值的时间也滞后于体应变状态。

In this paper, the aging dynamic characteristics of 2091 Al-Li alloy after superplastic forming at plane and volume strain states have been investigated respectively. The results show that the micro-hardness after aging increases greatly than that after superplastic forming. With the increament of aging period, the micro-hardness changes regularly. It is related with the disappearance of micro cavity, the decrease of cavity volume and the changes of microstructure. The hardness peak at plane strain state is lower than that at volume strain state. It takes longer aging period to reach the hardness peak at plane strain state than that at volume strain state for the same strain(ε)