(1. 攀钢集团研究院有限公司 钒钛资源综合利用国家重点实验室，攀枝花 617000；
2. 昆明理工大学 稀贵及有色金属先进材料教育部重点实验室，昆明 650093)
摘 要: 采用基于密度泛函理论(DFT)的第一性原理赝势平面波方法，计算Ti-Ni合金系中TiNi、Ti2Ni和TiNi3金属间化合物的平衡晶格常数、生成焓、内聚能、力学性质、德拜温度和电子结构。计算结果表明：TiNi、Ti2Ni和TiNi3金属间化合物均具有热力学稳定性且容易合金化生成，合金形成能力由强到弱的排序为TiNi3、TiNi、Ti2Ni；3种金属间化合物的晶体结构在能量上和力学上都是稳定的，结构稳定性由大到小排序依次为Ti2Ni、TiNi、TiNi3；TiNi和Ti2Ni为延性相(延展性Ti2Ni大于TiNi的)，TiNi3的延展性较差；3d电子是TiNi、Ti2Ni和TiNi3金属间化合物的最主要的成键电子，在这3种金属间化合物中，随着Ni相对含量的增加，平均成键电子数增多，共价键的比例增加，化学键的强度增强，金属性减弱，从而使得其弹性模量、硬度和德拜温度均逐渐升高。
关键字: Ti-Ni；金属间化合物；电子结构；力学性质；第一性原理
（1. Pangang Group Research Institute Co., Ltd., State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization, Panzhihua 617000, China;
2. Key Laboratory of Advance Material of Rare Precious and Nonferrous Metals, Kunming University of Science and Technology, Kunming 650093, China）
Abstract:The crystal structure, enthalpy of formation, cohesive energy, mechanical properties, Debye temperature and electronic structure of TiNi, Ti2Ni and TiNi3 intermetallic compounds were calculated by using first-principles ultrasoft pseudo-potential approach of the plane wave based on density functional theory (DFT). The calculated results show that three intermetallic compounds all have thermodynamic stability and are easy to form alloy. TiNi3 has the strongest alloys forming ability. The crystal structures of those intermetallic compounds are stable in energy and mechanics, the stability in descending order are as follows: Ti2Ni, TiNi, TiNi3. TiNi and Ti2Ni are ductile, and the ductility of Ti2Ni is significantly higher than that of TiNi. TiNi3 has a poor ductility. The 3d electronics are the mainly bonding electrons. As the increase of relative amounts of Ni in those intermetallic compounds, the average bonding electrons are growing, the strength of chemical bonds enhance, the metallicity weakens. This leads to gradually increase of the elasticity modulus, hardness and Debey temperature.
Key words: Ti-Ni; intermetallic compound; electronic structure; mechanical property; first-principle
