5A90铝锂合金Nd:YAG激光焊缝组织的晶粒形态与晶粒取向

采用Gleeble-1500D热模拟试验机进行热压缩实验,研究了TC4-DT钛合金在温度850～980℃、应变速率为0.001～10 s-1、变形量为50％条件下的热变形行为.根据应力-应变曲线分析了该合金的流变应力变化特点,建立了该合金的Arrhenius型本构方程及加工图.结果表明:流变应力随变形温度降低及应变速率增大而升高；变形温度与应变速率对TC4-DT合金应力影响显著；本实验测得的平均激活能为587.2 kJ/mol;该合金合适的加工条件为ε＜0.6 s-1,温度大于850℃.

Grain Shapes and Grain Orientations in Laser Welds of 5A90 Al-Li Alloys

The hot deformation behaviors of TC4-DT alloy in the temperature range of 850~980 oC and strain rate range of 0.001~10 s-1 have been studied by hot compressing testing on a Gleeble-1500D simulator at the deformation degree of 0.5. According to the stress-strain curves of the alloy and its stress characteristics, the Arrhenius constitutive equation and processing map were established. The results show that the flow stress increases with deformation temperature dropping and strain rate increasing.Deformation temperature and strain rate significantly influence the stress of TC4-DT alloy. The average activation energy is 587.2 kJ/mol. The suitable processing conditions of the alloy are the strain rate below 0.6 s-1 and the temperature greater than 850 oC.