摘要
Mg-2.7Nd-0.2Zn-0.4Zr （mass fraction, %） alloy was designed for degradable biomedical material. The ingots of the alloy were solution treated and then hot extruded. The extruded rods were heat treated with aging treatment, solution treatment and solution＋aging treatment, respectively. Microstructures of the alloy were observed by optical microscopy （OM） and scanning electron microscopy （SEM）. Mechanical properties at room temperature were tested. In vitro degradation behavior of the alloy immersed in simulated body fluid was measured by hydrogen evolution and mass loss tests. The degradation morphologies of the alloy with and without degradation products were observed by SEM. The results show that the grains grow apparently after solution treatment. Solution treatment improves the elongation of as-extruded alloy significantly and decreases the strength, while aging treatment improves the strength and reduces the elongation of the alloy. The yield ratio is reduced by heat treatment. The in vitro degradation results of the alloy show that solution treatment on the as-extruded alloy results in a little higher degradation rate and aging treatment on the alloy can reduce degradation rate slightly.
设计了Mg-2.7Nd-0.2Zn-0.4Zr(质量分数,%)镁合金作为可降解生物医用材料。对固溶处理后的铸锭进行了热挤压处理,然后对挤压棒分别进行了时效处理、固溶处理及固溶+时效处理。利用光学显微镜和扫描电镜观察了合金的组织,测试了合金的室温力学性能,采用析氢和失重法测试了合金在模拟体液中的降解行为,用扫描电镜观察了降解产物形貌及洗去降解产物后的形貌。结果表明:固溶处理后合金的晶粒明显长大,固溶处理显著提高挤压态合金的伸长率,但降低了合金的强度,而时效处理可提高合金的强度,降低合金的伸长率;热处理可降低合金的屈强比。体外降解实验结果表明:固溶处理使合金的降解速率稍微加快,而时效处理则能稍微减慢合金的降解速率。
基金
supported by the Introducing Talents Funds of Nanjing Institute of Technology,China
Project(20100470030) supported by the China Postdoctoral Science Foundation
