((上海交通大学 材料科学与工程学院，上海 200240))
摘 要: 采用基于密度函数理论的缀加平面波加局域轨道(APW+lo)方法和超晶胞方法对Nb含量为6.25%~37.5%Nb(摩尔分数)的Ti-Nb二元合金的能量、电子结构以及弹性性质进行了理论计算，研究Nb含量对Ti-Nb合金的β结构稳定性和弹性性质的影响。结果表明，随着Nb含量的升高，Ti-Nb合金的β结构稳定性提高，正方剪切常数C′以及弹性模量K、E和G呈单调增加。当Nb含量为9.87%时，正方剪切常数大于并接近于零，此时Ti-Nb合金的β结构稳定性最低，并具有最低的弹性模量。
关键字: 钛铌合金；结构稳定性；弹性性质；第一性原理
（(School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China)）
Abstract:The energetic, electronic structure and elastic property of Ti-Nb binary alloys with Nb contents ranging from 6.25% to 37.5% (mole fraction) were calculated using the method of supercell and augmented plane waves plus local orbitals within generalized gradient approximation. Based on the calculated results, the influences of Nb content on the β phase stability and elastic property of Ti-Nb alloys were investigated. The results show that the β phase stability, tetragonal shear constant C′, bulk modulus, elastic modulus and shear modulus of Ti-Nb alloys increase monotonously with increasing Nb content. When the Nb content is 9.87%, the tetragonal shear constant C′ of Ti-Nb alloy reaches nearly zero from positive, and meanwhile the alloy achieves the lowest phase stability and the lowest elastic modulus.
Key words: Ti-Nb alloy; phase stability; elastic property; first-principles
