回归再时效处理过程中AA7075铝合金的性能

摘要

采用回归法分别在180、240和320°C下热处理AA7075铝合金1、30、50、70、90和120 min.回归处理后,再在T6(120°C,24 h)热处理制度下对合金进行时效处理.通过V型冲击和硬度测试确定时效样品的力学性能,并通过测定电导率确定样品的物理性能.此外,利用光学显微镜和透射电镜表征合金的显微组织性能.结果表明,回归再时效的温度和时间对合金冲击韧性和硬度的影响与晶界的析出相有关.%A retrogression process was applied to AA7075 alloy at 180, 240 and 320 ℃for 1, 30, 50, 70, 90 and 120 min. After the retrogression, aging treatment was reapplied with T6 conditions (120 °C, 24 h). The mechanical properties of aged samples were determined by V-Charpy and hardness tests and also, physical properties of samples were determined by electrical conductivity tests. Moreover, microstructural properties were characterized by light microscope and transmission electron microscope. The results show that the effects of the temperature and the duration of the retrogression and reagent on the impact toughness and hardness are related to the precipitates at the grain boundary.