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

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. Biomedical Mg-xY-0.5Zn (x = 0.5, 1.0, 2.0, and 3.0 wt%) alloys are prepared by changing the Y content. The Y content affects the amount and morphology of the second phase. Among the alloys, the Mg-2Y-0.5Zn alloy has moderate mechanical properties and optimal corrosion resistance due to its uniform corrosion and low long-period stacked ordered/alpha-Mg potential difference.image (c) 2024 WILEY-VCH GmbH