Effect of heat treatment on stress corrosion behavior of 7075 aluminum alloy

The stress corrosion behavior of 7075 aluminum alloy in different tempers was studied using double cantilever beam(DCB) specimens.The results show that the stress corrosion susceptibility of 7075 aluminum alloy decreases according to the sequence of temper T6 G180 RRA T7351.In dry air,SEM observation of the fracture surface of 7075 alloys in different temper conditions was performed and it is found the ductile fracture pattern composed of dimples and tearing ridge prevails.However,in 3.5% NaCl solution,the fracture of 7075-T6 alloy with high stress corrosion susceptibility exhibits the characteristics of flat corrosion zones and ductile dimples,but the fracture pattern of 7075-G180 alloy with moderate stress corrosion susceptibility presents ductile fracture.