材料期刊网

An investigation was made into the influence of a retrogression and reaging treatment on the microstructure, tensile properties, and stress corrosion cracking resistance of 8090 Al-Li alloy. The results show that retrogression of the material at 230-degrees-C for 40 min or 325-degrees-C for 1.5 min, and then reaging to the peak aged condition, can result in an improved combination of tensile strength and stress corrosion cracking resistance. Through retrogression and reaging treatment, the alloy almost achieves the strength of the peak aged state and the stress corrosion cracking resistance of the overaged state. Transmission electron microscopy indicates that the delta' phase dissolves during retrogression and reprecipitates during reaging, thus increasing the strength. The T2 phase precipitates and grows during both retrogression and reaging, which results in the increase of stress corrosion cracking resistance.