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采用基于密度泛函理论的第一性原理计算方法,研究了Mo含量对Ti-xMo-Sn(x=l～5)合金相稳定性、弹性性质及其电子结构的影响,采用Voigt-Reuss-Hill近似方法估算了体系的多晶弹性模量,提出了低模量Ti-Mo-Sn合金的价电子准则,为医用钛合金的设计提供了理论基础.结果表明:Mo元素合金化能明显提高Ti-xMo-Sn合金的β相稳定性,所有合金都满足力学稳定性要求,随Mo元素含量增加,合金的体积模量B逐渐变大,而剪切模量G和杨氏模量E先减小后增大,其中Ti-3Mo-Sn具有最低的杨氏模量(48.47 GPa)和最佳的延展性,在生物医用领域展现出巨大潜力.Ti-xMo-Sn合金的弹性各向异性A与Mo元素含量有关,低弹性模量取向始终沿＜100＞晶体学方向.最后,结合Ti合金的总态密度(DOS)和分波态密度(PDOS)分析讨论了Mo元素对β相结构稳定性的影响机制.“,”The density functional theory(DFT)implemented in Vienna Ab-initio simulation package(VASP)code was employed to investigate the β phase stability and elastic properties of Ti-xMo-Sn(x=l～5)alloys.The structural properties were investigated after geometrical optimization.The general elastic properties(such as bulk modulus B,shear modulus G,Young’s modulus E)were estimated by Voigt-Reuss-Hill approximation.In addition,the valence electron criterion for design of low Young’s modulus Ti-xMo-Sn alloys was proposed.The calculated cohesive energy indicates that Mo can increase the β phase stability of Ti-xMo-Sn alloys.The Pugh ratio B/G and Poisson’s ratio v suggest that all these alloys exhibit ductile properties.For Ti-xMo-Sn alloys,the smaller tetragonal shear constant C’may induce the lower Young’s modulus.Ti-3Mo-Sn possesses the lowest Young’s modulus(48.47 GPa)and the best ductility,showing great potential for biomedical applications.The elastic anisotropy A of Ti-xMo-Sn alloys is sensitive to Mo concentration;the lowest Young’s modulus always orients in the＜100＞ crystallographic direction.In the end,total and partial DOS analysis was used to explain the calculated results.