Interesting phenomena for Al-Zn-Mg aluminum alloy after two years of storage: A comparative study on microstructure, mechanical properties and corrosion behavior of aluminum alloy with different aging treatments

[Display omitted] •Features of naturally aged (NA) and artificially aged (AA) alloys stored for two years were studied.•Microstructure of NA alloys has changed, while that of AA alloys is almost the same as two years ago.•Numerous finer precipitates better mechanical response and lower corrosion resistance of NA alloys.•Coarse precipitates and high-density dislocations limit the elongation of AA alloys.•The better protective rust and weaker galvanic effect improve the corrosion resistance of AA alloys. This work presents a comparison of microstructure, mechanical properties and corrosion behavior of naturally aged (NA) and artificially aged (AA) alloys after two years of storage. The results showed that numerous finer precipitates distributed in NA alloys, resulting in better mechanical response but higher corrosion sensitivity, while the microstructure of AA alloys were almost the same as two years before, the tensile results showed the initial necking phenomenon but limited elongation caused by presence of coarse precipitates and high-density dislocations, whilst its corrosion resistance was better than NA alloys, reflecting from smaller pits and more protective components of corrosion products.