Effect of selective oxidation on corrosion behavior of Mg-Gd-Y-Zn-Zr alloy

The multilayer features are observed in the microstructures of Mg-Gd-Y-Zn-Zr alloy after high-heat treatment. The microstructures of the heat-treated samples in depth can be divided into four zones: the rare earth (RE) oxide film, the layer without long-period stacking ordered (LPSO) phases, the lamellar LPSO layer and the blocky LPSO zone. The corrosion behavior of peak-aged samples was investigated. The results indicate that the RE-rich scale and the LPSO-free layer, which are generated as the result of selective oxidation during high-heat treatment, significantly improve the corrosion resistance of Mg-Gd-Y-Zn-Zr alloy.