Effect of pre-strain on microstructure and stress corrosion cracking of over-aged 7050 aluminum alloy

The effect of pre-strain on the microstructure and stress corrosion cracking of over-aged 7050 aluminum alloy was investigated. In the over-aged 7050 alloy the η- (MgZn2) phase was the main precipitates. The size of the η-phase particles within grains increased with increasing the pre-strain deformation, which resulted in the reduction in the mechanical strength of the alloy. Compared to that of the sample without pre-strain, the precipitates in the grain boundaries of pre-strained samples became smaller and tended to form relatively continuous distribution with increasing the pre-strain percents, resulting in a continuous decrease in the stress corrosion cracking (SCC) resistance.