Effect of Y Contents on the Microstructure, Mechanical Properties, and Corrosion Behavior of Biomedical Mg–0.5Zn Alloy

Abstract

The effects of Y contents on the microstructure, mechanical properties, and corrosion resistance of biomedical Mg–0.5Zn alloy are investigated. In the results, it is shown that an increase in Y content leads to a growth in the amount of the second phase and a decrease in the spacing of the secondary dendrite arms. Additionally, the second phase changes from a uniformly dispersed point‐like shape to a semicontinuous reticular distribution. Meanwhile, the addition of Y obviously reduces the dendritic organization and this contributes to the improvement of mechanical properties. The corrosion resistance of the alloys increased first when Y content is 2 wt% at most, and then decreases in Mg–3Y–0.5Zn alloy. The gradual improvement of corrosion resistance in Mg–1Y–0.5Zn and Mg–2Y–0.5Zn is closely related to the formation of the compact corrosion layer including Y element, while the sudden drop corrosion resistance of Mg–3Y–0.5Zn alloy is mainly attributed to the presence of a great deal of semicontinuous long‐period stacked order and its excessive negative potential compared with Mg matrix, which leads to a severe pitting.