In-situ electrochemical analytical effect of aging treatment on stress corrosion behavior of Al–Zn–Mg–Cu aluminum alloy

The stress corrosion cracking (SCC) behavior of Al–Zn–Mg–Cu alloys in different aging treatment states was dynamically studied by slow strain rate tensile (SSRT) combining in-situ electrochemical impedance spectroscopy (EIS). By analyzing the influence of microstructure and precipitation phase on stress corrosion resistance under different aging conditions, it was found that the stress corrosion process can be divided into three stages, the corresponding charge transfer resistance (Rct) shows three evolutionary patterns, with the maximum value occurred when the alloys were under the maximum stress. The regression re-aging (RRA) treatment obtained coarse and discrete grain boundary precipitates (GBPs) with higher Cu content, which improved the SCC resistance of alloys significantly.