In this work, we investigated the effect of yttrium(Y) on microstructure, the mechanical and corrosion properties and the cytotoxicity of Zn-1.5Mg-xY(x=0, 0.2, 0.5wt%) alloys prepared by casting and extrusion. The results showed that the microstructure of extruded Zn-1.5Mg-xY alloys consisted of α-Zn matrix, Mg2Zn11 particles and Y containing blocks. The tensile strength and compressive strength of Zn-1.5Mg-xY alloys improve with the increase of Y content. Alloying with Y also had an impact on the corrosion resistance of Zn-Mg alloys. In terms of toxicity, the cells cultured in the leachate of Zn-1.5Mg-xY alloys with concentrations of 25% and 50% showed good growth morphology with the relative proliferation rate (RGR) values being greater than 100% and the cytotoxicity level being 0, the addition of Y has little effect on the compatibility of alloy with cells.

Mg-3Zn-0.5Sr-xCa(wt.%) (x=0, 0.2, 0.5) alloys were fabricated by casting and hot extrusion. X-ray diffraction (XRD) and optical microscopy observation showed that the microstructure of Mg-3Zn-0.5Sr-xCa alloys was composed of α-Mg matrix and Mg17Sr2 phase precipitated along grain boundaries. The tensile strength of the alloy increased from 255MPa to 305MPa with increasing Ca content from 0 to 0.5wt%, but the elongation to fracture of the alloys was 19.45%, 28.7% and 15.2% respectively, indicating that coarse precipitation increased the risk of crack initiation and propagation along the grain boundaries leading to reduced ductility of Mg alloys. The polarization curves revealed that Mg-3Zn-0.5Sr-0.2Ca has the highest corrosion potential and the lowest corrosion current density indicating the optimum corrosion resistance. In cytotoxicity test, Mg-3Zn-0.5Sr-xCa alloys were harmless to mouse osteoblastic and Mg-3Zn-0.5Sr-0.2Ca alloy exhibited optimal biocompatibility.