热处理温度对生物医用Ti87Nb8Sn5合金微观组织和力学性能影响

Effect of heat treatment temperature on microstructure and mechanical properties of biomedical Tig7NbsSn5 alloy

采用X射线衍射仪、光学显微镜、万能试验机、显微硬度计以及纳米压痕仪等研究了不同热处理温度下Ti87Nb8Sn5合金的显微组织和力学性能。结果表明:铸态和在773 K热处理下合金的组织是由大量α-Ti相和少量的第二相Ti3Sn相所组成,在873 K和973 K热处理下合金的组织是由大量的α-Ti和少量β-Ti相所组成。室温铸态试样以及在773 K热处理试样的应力-应变曲线呈现出超弹性;而在873 K和973 K热处理的合金具有高的屈服强度,大的塑性形变以及大的弹性能。在873 K和973 K热处理下合金的约化弹性模量(Er)值分别为43.3 GPa和36.2 GPa,接近人骨的弹性模量值(10~30 GPa)。另外,在873 K和973 K热处理下合金具有大的H/Er和H^3/Et^2值,说明了该热处理条件下合金分别具有高的耐磨抗力和高的耐磨性。

Microstructure and mechanical properties of Ti87Nb8Sn5 alloy at different heat treatment temperatures were studied by means of X-ray diffractometer, optical microscope, universal testing machine, microhardness meter and nano-indentation instrument. The results show that the as-cast alloy and the alloy after heat treatment at 773 K are composed of a large number of α-Ti phase and a small number of second Ti3 Sn phase. The microstructure of the alloy after heat treatment at 873 K and 973 K is composed of a large number of α-Ti phase and a small number of β-Ti phase. The stress-strain curves of the as-cast alloy at room temperature and the alloy after heat treatment at 873 K show hyperelasticity, while the alloy after heat treatment at 873 K and 973 K has high yield strength, large plastic deformation, and large elastic energy. The reduced elastic modulus(Er) values of the alloy after heat treatment at 873 K and 973 K are 43.3 GPa and 36.2 GPa, respectively, close to the elastic modulus values of human bone(10-30 GPa). Moreover, the alloy has large H/Er and H^3/Et^2 values after heat treatment at 873 K and 973 K, which indicates that the alloy has high wear resistance and high anti-wear ability, respectively.