Effect of cerium on microstructure, mechanical properties and corrosion properties of Al-Zn-Mg alloy

The effects of trace Ce on the microstructure, mechanical properties and corrosion resistance of Al-Zn-Mg alloy were studied by means of metallographic analysis, scanning electron microscopy (SEM), mechanical tensile test, slow strain rate tensile test, cyclic polarization curve test, electrochemical impedance spectroscopy test and anodic oxidation test. The results show that the addition of trace Ce has little effect on the strength of Al-Zn-Mg alloy, but can significantly improve the corrosion resistance of the alloy; The mechanical properties and corrosion resistance of the alloys decrease significantly with the addition of excessive Ce; the addition of 0.04 wt% Ce can reduce significantly the self-corrosive current density of Al-Zn-Mg alloy and increase obviously passivation film resistance of the alloy. The stress corrosion sensitivity index decreases from 0.612 to 0.219, which improves the corrosion resistance properties significantly.