中文摘要：

采用密度泛函理论的缀加平面波加局域轨道的第一性原理和超晶胞方法对β结构的Ti75Nb25以及Ti68.75Nb25X6.25（X为Mo,Sn,Ta和Zr）合金的能量、电子结构以及弹性性质进行了理论计算。通过对比这几种合金的结构稳定性和弹性性质,发现Mo和Ta元素既能起到稳定β-Ti25Nb相作用,又能使其弹性常量增加。而Sn对β结构的稳定性影响较小,Zr却降低了β结构的稳定性,且两者对弹性常数的影响均较小。

英文摘要：

The energy,electronic structure and elastic properties of β-phase Ti75Nb25 and Ti68.75Nb25X6.25（X=Mo,Sn,Ta,Zr）alloys were calculated using the method of supercell and based on density functional theory（DFT） augmented plane waves plus first-principles of local orbitals within generalized gradient approximation.Comparing the structure stability and general elastic properties between Ti68.75Nb25X6.25 alloys,the results show that Mo and Ta can stabilize the β phase and increase the elastic constants.Sn affects slightly on the structure stability of β phase while Zr decreases it and both of them have a little influence on the elastic constants of the β-phase Ti75Nb25.