2195铝锂合金热模拟平面应变压缩行为研究

Plane strain compression behavior of 2195 Al-Li alloy by thermal simulation compression

摘要:

2195铝锂合金被认为是航空航天领域的理想结构材料，吸引了广大研究学者的兴趣，但其热变形行为的研究却相对较少。本文通过热模拟平面应变压缩试验，研究了2195铝锂合金的热变形行为，变形温度为400~500 ℃，应变速率为0.01~10 s-1。研究表明，材料变形呈稳态流变特征，随变形温度增加，应变速率降低，流变应力逐渐减小，合金具有正应变速率敏感性。建立了2195铝锂合金材料本构方程，其激活能值为214.937KJ/mol。通过分析加工图，得到材料的适宜加工区为应变速率接近0.01 s-1，温度为475~500 ℃。最后通过分析动态软化过程中的应力规律，得到了材料软化机制判定方程。

Abstract:

2195 Al-Li alloy is identified as an ideal structural material for aerospace field, but limited research on its hot deformation behavior has been found in open publication. In this study, isothermal plane strain compression test was conducted on Gleeble-3500 thermal mechanical simulator, experimental temperature range from 400 ℃ to 500 ℃ and strain rate various from 0.01 s-1 to 10 s-1. The results show that flow stress decreases with increasing temperature and decreasing strain rate. Constitutive model based on the hyperbolic-sine equation was established to describe relationship between flow stress and deformation temperature, strain rate. The apparent activation energy of plane strain compression was estimated to be 217 KJ / mol. To evaluate the hot workability of this alloy, the processing maps at strains of 0.5 and 0.7 were constructed on the basis of dynamic material model and Prasad’s instability criterion. Optimum parameters were obtained in the temperature of 475~500 ℃, strain rate of 0.01 s-1 for plane strain compression.