7055超强铝合金时效硬化特性与应力腐蚀性能研究

Study on the Ageing Behavior and Stress Corrosion Cracking(SCC) Behavior of 7055 Ultrahigh-strength Aluminium Alloy

研究了７０５５超强铝合金挤压板材的时效硬化特性和应力腐蚀性能。结果表明：７０５５铝合金在１２０℃长期单级时 效存在三峰强化现象，三峰位置分别在 ３０ ｈ、１０５ ｈ、１３０ ｈ，其主要强化相分别为 ＧＰ区、η’相和η相，其第一峰出现 比７０５０、７１７５合金的推迟６ｈ。另外，随时效时间延长，７０５５合金的应力腐蚀敏感性指数降低，合金的抗应力腐蚀性能 变好。

The ageing behavior and stress corrosion cracking (SCC) behavior of 7055 ultrahigh-strength aluminium extruded plates were studied. The results indicate: A new phenomenon of three peak hardening dring 120℃ long term ageing progress is observed. The three hardening peaks are respectivel at 30h, 105 h, and 130 h. The main hardenng phrases are respectively GP zone, η' precipitates and η precipitates. Compared to 7050 and 7075 aluminium alloys, the first hardening peak at 120℃ is later by 6h. At the same time, with the ageing time increasing the SCC susceptibillty index of 7055 aluminium alloy is decreasing, and the resistance to stress corrosion (SCR) is increasing.