Mg-2Zn-0.2Sr-0.6Zr-1Nd医用可降解镁合金显微组织、力学性能及耐蚀性能的研究

Microstructure,Mechanical Properties and Corrosion Resistance of Mg-2Zn-0.2Sr-0.6Zr-1Nd Medical Degradable Magnesium Alloy

研究和比较了铸态、均匀化态和挤压态Mg-2Zn-0.2Sr-0.6Zr-1Nd合金的微观组织、力学性能及耐蚀性能。微观组织观察结果表明,与铸态合金相比,均匀化态的镁合金晶粒尺寸略有降低,且相比于铸态和均匀化态合金,挤压态镁合金晶粒尺寸最为细小。室温拉伸试验结果表明,与铸态合金相比,均匀化态镁合金屈服强度和抗拉强度略有增加,伸长率大幅提高;同时,挤压态镁合金伸长率略有增加,屈服强度和抗拉强度大幅提高。另外,通过Kokubo模拟体液浸泡试验获得Mg-2Zn-0.2Sr-0.6Zr-1Nd合金铸态、均匀化态和挤压态的腐蚀速率分别为1.67 mm/a、1.23 mm/a和0.39 mm/a,这表明挤压态镁合金耐蚀性能最为优异,这主要归因于晶粒细化和Mg;Sr;相的消失。

The microstructure, mechanical properties and corrosion resistance of as-cast, homogenized and extruded Mg-2 Zn-0.2 Sr-0.6 Zr-1 Nd alloys were studied and compared. The microstructure observation results show that the grain size of the homogenized magnesium alloy was slightly reduced compared with the as-cast alloy, and the grain size of the extruded magnesium alloy was the smallest compared with the as-cast and homogenized alloys. The tensile test results at room temperature show that, compared with the as-cast alloy, the homogenized magnesium alloy had a slight increase in yield strength and tensile strength, and the elongation rate was greatly improved;at the same time, compared with the as-cast alloy, the extruded magnesium alloy had a slight increase in elongation, and the yield strength and tensile strength were greatly improved. In addition, the corrosion rates of the Mg-2 Zn-0.2 Sr-0.6 Zr-1 Nd alloys were obtained through the Kokubo simulated body fluid immersion experiment. The corrosion rates of the as-cast, homogenized state and extruded state alloys were 1.67 mm/a, 1.23 mm/a and 0.39 mm/a, respectively, indicating the extruded state magnesium alloys have the most excellent corrosion resistance, which is mainly due to the grain refinement and the disappearance of Mg;Sr;phase.