The effects of Sn content on the corrosion behavior and mechanical properties of Mg-5Gd-3Y- x Sn-0.5Zr alloys.

The effects of Sn content on the corrosion behavior and mechanical properties of Mg-5Gd-3Y-0.5Zr alloy were studied by SEM, EDS, XRD and electrochemical testing. Results show that Sn can refine the grain size and promote the precipitation of Mg 5 (Gd,Y) phase. When the Sn content is 1.5-2 wt%, a needle-like Mg 2 Sn phase will be precipitated in the alloy. Mg-5Gd-3Y-1Sn-0.5Zr alloy had the lowest corrosion rate, which is attributed to the barrier effect of the grain boundary and dispersed Mg 5 (Gd,Y) phase on corrosion. However, the Mg 2 Sn phase formed by excessive Sn addition will accelerate galvanic corrosion. At the same time, Mg-5Gd-3Y-1Sn-0.5Zr alloy had best mechanical properties. In 1.5Sn and 2Sn alloys, the cleavage effect of the needle-like Mg 2 Sn phase on the matrix reduced mechanical properties.