CAJ | 학술논문

采用基于密度泛函理论的第一性原理计算方法研究了过渡族金属钛硼化物(Ti2B,TiB和TiB2)的晶体参数、力学性能和电子性质.晶格参数的计算结果与实验值以及其它理论计算值吻合得很好.弹性常数的计算结果表明,这3种硼化物在常压下都是力学稳定的.与金属钛相比(120 GPa),3种硼化物的体弹模量都很大且随着硼含量的增加而增加,这可能是由金属晶格中引入的硼原子与钛原子之间形成定向共价键引起的.除TiB2外,TiB具有较大的体弹模量和剪切模量,可以视作为一种具有良好抗压性质的硬质材料.此外,对这几种硼化物的弹性各向异性性质和德拜温度也进行了讨论.电子态密度和原子电荷布居分析表明,这3种硼化物的化学键成分同时包含了共价、离子和金属成分.
채용기우밀도범함이론적제일성원리계산방법연구료과도족금속태붕화물(Ti2B,TiB화TiB2)적정체삼수、역학성능화전자성질.정격삼수적계산결과여실험치이급기타이론계산치문합득흔호.탄성상수적계산결과표명,저3충붕화물재상압하도시역학은정적.여금속태상비(120 GPa),3충붕화물적체탄모량도흔대차수착붕함량적증가이증가,저가능시유금속정격중인입적붕원자여태원자지간형성정향공개건인기적.제TiB2외,TiB구유교대적체탄모량화전절모량,가이시작위일충구유량호항압성질적경질재료.차외,대저궤충붕화물적탄성각향이성성질화덕배온도야진행료토론.전자태밀도화원자전하포거분석표명,저3충붕화물적화학건성분동시포함료공개、리자화금속성분.
The first-principle calculations are performed to investigate the structural,mechanical and electronic properties of titanium borides (Ti2B,TiB and TiB2).Those calculated lattice parameters are in good agreement with the experimental data and previous theoretical values.All these borides are found to be mechanically stable at ambient pressure.Compared with parent metal Ti (120GPa),the larger bulk modulus of these borides increase successively with the increase of the boron content in three borides,which may be due to direction bonding introduced by the boron atoms in the lattice and the strong covalent Ti—B bonds.Additionally,TiB can be regarded as a candidate of incompressible and hard material besides TiB2.Furthermore,the elastic anisotropy and Debye temperatures are also discussed by investigating the elastic constants and moduli.Electronic density of states and atomic Mulliken charges analysis show that chemical bonding in these titanium boddes is a complex mixture of covalent,ionic,and metallic characters.