Characterization of a Mg95.5Zn1.5Y3 alloy both containing W phase and LPSO phase with or without heat treatment

Abstract

Abstract The influence of solid solution treatment on the microstructure and corrosion resistance of as-cast Mg 95.5 Zn 1.5 Y 3 alloy is characterized. The microstructure of the as-cast Mg 95.5 Zn 1.5 Y 3 alloy mainly consisted of α-Mg, W (Mg 3 Zn 3 Y 2 ) phase, and the long period stacking ordered (LPSO) (Mg 12 ZnY) phase. After solid solution treatment, most of the W phase disappears gradually with increasing solution treatment time, with only a small amount of W phase distributed as particle. The LPSO phase slightly dissolved into substrate, and its morphology transitions from blocky shape to rod shape. Solid solution treatment of Mg 95.5 Zn 1.5 Y 3 exhibits excellent corrosion resistance, because the Y and Zn atoms became enriched in the matrix and the changed morphologies of the LPSO and W phases were modified through heat treatment. The alloy created with solid solution treatment at 520 °C for 10 hours exhibits corrosion potential of −1.419 V, suggesting a significant improvement in corrosion performance.