Investigation of microstructure and corrosion resistance of an Al-Zn-Mg-Cu alloy under various ageing conditions

In this study, transmission electron microscopy and 3D optical profilometer were employed to investigate the effects of single-stage ageing and regression re-ageing treatments on the microstructure and corrosion resistance of Al-Zn-Mg-Cu alloy. The results indicate the intergranular corrosion resistance is increased by 36% with the regression re-ageing. Based on the semi-elliptical damage model, a 3D expansion model for pits is established. Meanwhile forms a systematic study of the formation mechanism, nucleation and growth of corrosion pits. This will contribute to the systematic and in-depth study of the corrosion resistance of Al-Zn-Mg-Cu alloy in aviation applications.