7050铝合金搅拌摩擦焊接头腐蚀行为分析

Corrosion behavior of friction stir welded joints of 7050 aluminum alloy

7050高强铝合金被广泛应用于飞机的承力构件、火箭舱段、导弹、飞船等空间载荷承力结构的制备.航空航天飞行器服役环境恶劣(雷电、雨水、辐射、除冰液等),对腐蚀性能特别是应力腐蚀开裂性能有较高的要求,然而高强铝合金FSW接头在特定服役环境下的接头性能数据包括腐蚀性能尚不完善.基于此,文中重点研究不同焊接热输入对接头腐蚀行为的影响.采用晶间腐蚀、四点弯曲应力腐蚀试验,选择不同的加载应力,揭示高强铝合金腐蚀行为.结果表明,高强铝合金应力腐蚀敏感性强,不论是优化焊接参数,还是改变热输入,单纯通过焊接过程本身控制很难改善应力腐蚀敏感性.

The 7050 high-strength aluminum alloy is widely used in the manufacture of aircraft load-bearing components,rocket chamber sections,missiles and loadbearing structures of spacecraft.The aircraft always service in harsh environments,such as lightning,rain,radiation,deicing fluid,and so on.So there is high requirement for corrosion performance,especially stress corrosion cracking.However,in the specific service environment,the properties of high-strength aluminum alloy FSW joints including corrosion resistance are imperfect.Based on this,this article focused on the influence of different welding heat input on the corrosion behavior of joints.We selected different loading stresses,via the intergranular corrosion,four point bending stress corrosion text to reveal the corrosion behaviors of the high-strength aluminum alloy.The results indicated that high-strength aluminum alloy stress corrosion resistance is sensitive.Whether to optimize welding parameters or change the heat input,it is difficult to improve stress corrosion resistance by simply controlling the welding process itself.