Mg，Ca元素对可降解Zn合金组织性能影响

摘要 采用X射线衍射、扫描电子显微镜、光学显微镜、室温拉伸和浸泡失重法研究了挤压态纯Zn和Zn-0.2Mg-xCa(x=0，0.06，0.15，0.3)(质量分数)合金微观组织、力学性能和体外降解速率.结果表明:200℃挤压后，纯Zn晶粒尺寸达到100μm;Zn-0.2Mg-xCa合金中晶粒尺寸均维持在15~20μm之间，并存在第二相Mg2Zn11和CaZn13.随着Ca含量增加，CaZn13含量逐渐增加，且当Ca质量分数达到0.15%以上时CaZn13尺寸达到15~50μm.纯Zn的屈服强度和延伸率分别为64MPa和14%，Zn-0.2Mg-xCa合金随着Ca含量增加屈服强度由180MPa提高到约200MPa，延伸率则逐渐由18%降低到6%.纯Zn和Zn-0.2Mg-xCa合金在SBF溶液中降解速率维持在0.05~0.15mm·a-1，而且随Ca的添加降解速率略有降低.
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.