Comparison of strength, stress corrosion cracking and microstructure of new generation 7000 series aluminium alloys

Abstract

The strength, stress corrosion cracking (SCC), and microstructure of four typical new generation 7000 series aluminium alloys (AA7037, AA7097, AA7056, and AA7085) under three-stage aging heat treatment have been investigated. The results showed that AA7085 exhibited the highest SCC resistance while AA7037 displayed the lowest SCC resistance. In addition, AA7056 presented the higher strength and SCC resistance compared with AA7037. The more susceptible to SCC of new generation 7000 series aluminium alloys was mainly ascribed to the high Zn and low Cu content in grain boundary precipitates. The results provided a new insight for the composition design of new generation 7000 series aluminium alloys.