Abstract: Pure Zn and Zn-0.2Mg-xCa (x=0， 0.06， 0.15 and 0.3，mass fraction) alloys were prepared by indirect hot extrusion. The microstructure， mechanical properties and in vitro degradation rate of extruded Zn-based alloys were investigated by X-ray diffraction， scanning electron microscopy， optical microscope， tensile test and immersion test. The results showed that pure Zn consisted of equiaxed grains with the size of 100μm and Zn-0.2Mg-xCa alloys were composed of refined grains with the size of 15~20μm and the second phases of Mg₂Zn₁₁ and CaZn₁₃. With increasing Ca addition， the amount of CaZn₁₃ increased and the size of CaZn₁₃ reached 15~50μm when the Ca mass fraction was over 0.15%. The yield strength and elongation of pure Zn was 64MPa and 14%， respectively. With increasing Ca addition， the yield strength of Zn-0.2Mg-xCa increased from 180MPa to 200MPa， while the elongation decreased from 18% to 6%. The degradation rate of Zn and Zn-0.2Mg-xCa kept between 0.05~0.15mm·a^-1 and decreased with Ca addition.

Key words: Zn-Mg-Ca alloys, indirect hot extrusion, microstructure, mechanical property, degradation rate