【摘要】 采用基于密度泛函理论的第一原理方法,研究了Ti-V系合金Ti₃V, TiV和TiV₃的晶体结构,电子结构及力学性质.结果表明, TiV₃结构最稳定,其次是TiV,而Ti₃V稳定性最弱,但是, Ti₃V形成能力最强.三种合金的自间隙构型中,与Ti的自间隙构型相比,更容易形成V的自间隙构型;不管是Ti自间隙还是V自间隙, TiV₃的自间隙形成能均最大.力学性质的计算表明:三种合金均满足力学稳定性标准,且都为韧性材料;体模量及硬度计算表明, TiV₃的硬度最高,其次是TiV, Ti₃V的硬度最低,这与自间隙能的计算结果一致.电子结构计算表明:在费米能级处,三种合金均主要由Ti, V的p, d轨道电子提供态密度, TiV₃合金电子结构最稳定.差分电荷密度计算表明:在Ti₃V合金中,金属性强于共价性.在Ti₃V, TiV, TiV₃三种合金中,金属性逐渐减弱,共价性逐渐增强,合金变得稳定.更多还原

【Abstract】 The crystal structures, electronic structures and mechanical properties of Ti₃V, TiV and TiV₃ of Ti-V alloys were studied by using the first principle method based on density functional theory. The results show that TiV₃ has the most stable structure, followed by TiV, Ti₃V has the weakest stability, but Ti₃V has the strongest formation ability. Compared with the self-interstitial configuration of Ti, the self-interstitial configuration of V is easier to be formed. Whether it is Ti self-interstitial or V self-interstitial, the formation energy of self-interstitial of TiV₃ is the largest. The calculation of mechanical properties shows that all three alloys meet the mechanical stability standard and are ductile materials. The calculation of volume modulus and hardness shows that TiV₃ has the highest hardness, TiV follows, Ti₃V has the lowest hardness, which is consistent with the calculation results of self-interstitial energy. The electronic structure calculation shows that at the Fermi level, the state densities of the three alloys are mainly provided by the p and d orbitals of Ti and V, and the electronic structure of the TiV₃ alloy is the most stable. Differential charge density calculation shows that metallic properties are stronger than covalency in Ti₃V alloy. In Ti₃V, TiV and TiV₃ alloys, the metallicity decreases and the covalency increases gradually, and the alloy becomes stable.更多还原