Abstract: Mg-1.5Y-1.2Zn-0.44Zr alloys by adding small amounts(mass fraction) of yttrium(1.5%), zinc(1.2%) and zirconium(0.35%) into pure magnesium were developed as degradable metallic biomaterials. Also, solution treatment and hot extrusion were used as the methods for fabrication. An investigation of microstructure and in vitro degradation responses were made. The alloys are mainly composed of the matrix α-Mg phases and the Mg12ZnY secondary phases. The grains of the as-cast alloys were significantly refined by hot extrusion. The biodegradation resistance of the as-cast alloys is obviously improved by hot extrusion via microstructure refinement. The results of in vitro degradation responses in the simulated body fluid(SBF) indicate that the product of degradation precipitated on the alloy′s surface is the phosphate which contains Ca and Mg elements.

Key words: biomaterials, Mg-Y-Zn-Zr, microstructure, in vitro degradation