Effects of Zn on the microstructure, mechanical property and bio-corrosion property of Mg-3Ca alloys for biomedical application

The effects of the addition of Zn element on the microstructures, mechanical properties and bio-corrosion properties of Mg-3Ca alloys are investigated. The microstructure and X-ray diffraction topography indicate that as-cast Mg-3Ca alloys are composed of primary Mg and eutectic (α-Mg + Mg₂Ca) phases, while Mg-3Ca-2Zn alloys are constituted of primary Mg and eutectic (α-Mg + Mg₂Ca + Ca₂Mg ₆Zn₃) phases. Mechanical properties results show that the element Zn could improve both tensile strength and elongation of Mg-3Ca alloys. The ultimate tensile strength is enhanced by 22%. Meanwhile, the corrosion resistance is increased by the addition of Zn element. It is thought that the presence of Ca₂Mg₆Zn₃ phase mainly contributes to these improvements. Mg-3Ca-2Zn alloy provides moderate strength and excellent corrosion resistance for biomedical application.