2099铝锂合金腐蚀性能

通过光学显微镜观察、透射电镜分析和慢应变速率拉伸试验,研究了2099铝锂合金在不同时效条件下的晶间腐蚀行为、剥落腐蚀行为、应力腐蚀行为和微观组织。结果表明:随着时效时间的延长,合金的耐腐蚀性能得到改善。在欠时效条件下,晶界上残余AlCuFeMn相的存在,导致合金耐腐蚀性能较差;峰时效条件下,大量T1相在基体的均匀析出,改善了合金的耐腐蚀性能;在过时效条件下,大量T1相保持峰时效状态的形貌特征,晶界析出相呈粗大不连续分布,从而使合金的耐腐蚀性能进一步提高。

Corrosion Properties of 2099 Al-Li Alloy

The intergranular corrosion behavior, exfoliation corrosion behavior, stress corrosion behavior and microstructures of 2099 Al-Li alloy in different aging conditions were investigated by OM, TEM and slow strain rate tensile testing. The results show that the corrosion resistance of the alloy is improved with aging time. In the under-aged condition, the remained AlCuFeMn phases at grain boundaries result in low corrosion resistance of the under-aged alloy. In the peak-aged condition, many T1 phases precipitate in the matrix, promoting the incensement of corrosion resistance of the alloy. In the over-aged condition, a great number of T1 phases still remain the morphology as that in the peak-aged alloy, and the coarse precipitates distribute along the grain boundaries with large space inducing the further growth of corrosion resistance of the alloy.