Microstructures and mechanical properties of as cast Mg-Zr-Ca alloys for biomedical applications

The microstructures and mechanical properties of as cast Mg-Zr-Ca alloys were investigated for potential use in biomedical applications. The Mg-Zr-Ca alloys were fabricated by commercial pure Mg (99.9 mass-%), Ca (99.9 mass-%) and master Mg-33 mass-% Zr alloy. The microstructures of the alloys were examined by X-ray diffraction analysis and optical microscopy, and the mechanical properties were determined from tensile tests. The experimental results indicate that the Mg-Zr-Ca alloys with 1 mass-% Ca are composed of one single a phase; these alloys with 2 mass-% Ca consist of both Mg2Ca and alpha phase, and all the alloys exhibit typical coarse microstructures. An increase in Zr increases the strength of Mg-Zr-Ca alloys with 1 mass-% Ca, and the formation of Mg2Ca decreases the strength of the alloys. Mg-1Zr-1Ca alloy (mass-%) has the highest strength and best ductility among all the studied alloys.