生物材料用Mg-Y-Zn-Zr合金的微观结构及体外降解行为

摘要

通过向纯镁中添加微量的合金化元素(Y、Zn和Zr),采用熔融浇铸法制备了名义成分为Mg-1.5Y-1.2Zn-0.44Zr四元可降解镁合金生物材料,并对其进行了均匀化处理和挤压.对这3种状态的镁合金进行了微观结构及在模拟体液(SBF)中体外降解行为的测试和分析,结果表明,合金主要由α-Mg基体和MgI2ZnY第二相组成；合金经过挤压后的组织得到了明显的细化；因此挤压后合金的降解性能得到明显改善；合金在模拟体液中生成的降解产物主要是含Ca和Mg的磷酸盐.%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.