Influence of high-temperature pre-precipitation on local corrosion behaviors of Al–Zn–Mg alloy

The effects of high-temperature pre-precipitation treatment on the microstructure, age-hardening, stress corrosion cracking, inter-granular corrosion and exfoliation corrosion of Al–Zn–Mg alloy have been investigated. High-temperature pre-precipitation can enhance the distribution discontinuity of grain boundary precipitates, increase the Cu content in grain boundary precipitates and lead to the increase in the critical stress intensity factor in salt solutions with the same strength and ductility. In addition, Al–Zn–Mg alloy with pre-precipitation treatment has an enhanced resistance to inter-granular and exfoliation corrosion.