Cu-Zr系二元合金化合物的第一性原理研究

First-Principles Investigationof Cu-Zr Binary Alloy Compounds

采用基于密度泛函理论的第一性原理,通过计算7种Cu-Zr系二元合金化合物的能量、态密度、能带结构以及弹性常数,系统地研究了各化合物的热力学性质、电子结构和力学性质。热力学性质计算结果表明:7种化合物均为热力学稳定相,其中Cu_(8)Zr_(3)和Cu_(10) Zr_(7)相对较易生成,其生成焓分别为^(-1)6.57 kJ·mol^(-1)和^(-1)6.38 kJ·mol^(-1);CuZr_(2)结合得最稳定,其结合能为-614.94 kJ·mol^(-1)。电子结构计算结果表明:7种化合物均具有金属特性,其中Cu_(5)Zr、Cu_(5)1 Zr_(14)、Cu_(8)Zr_(3)、Cu_(10) Zr_(7)、CuZr和CuZr_(2)为导体,而Cu_(2)Zr呈现半导体性质。力学性质计算结果表明:Cu_(5)1 Zr_(14)为力学不稳定相,其余6种为力学稳定相,其中,Cu_(8)Zr_(3)抵抗外力的能力最强,延性最好,Cu_(5)Zr的硬度最高,CuZr_(2)的脆性最大。另外,6种力学稳定相的德拜温度计算结果表明:Cu_(10) Zr_(7)的共价键的强度相对较高,而CuZr的共价键的强度相对较低。

Based on the first-principles of density functional theory,the thermodynamic properties,electronic structure and mechanical properties of seven Cu-Zr binary alloy compounds were systematically studied by calculating the energy,density of states,band structure and elastic constants.The calculation results of thermodynamic properties show that all the seven compounds are thermodynamic stable phases.Among them,Cu_(8)Zr_(3) and Cu_(10) Zr_(7) are relatively easy to generate,and their formation enthalpies are^(-1)6.57 kJ/mol and^(-1)6.38 kJ/mol,respectively;CuZr_(2) is the most stable phase with binding energy of-614.94 kJ/mol.The results of electronic structure calculation show that all of the seven compounds have certain metal properties.Cu_(5)Zr,Cu_(5)1 Zr_(14),Cu_(8)Zr_(3),Cu_(10) Zr_(7),CuZr and CuZr_(2) are conductors,while Cu_(2)Zr is semiconductor.The calculation results of mechanical properties show that Cu_(5)1 Zr_(14) is the mechanical unstable phase,and the other six are the mechanical stable phase.Among the six mechanical stable phases,Cu_(8)Zr_(3) has the strongest resistance to external forces and the best ductility.Cu_(5)Zr has the highest hardness and CuZr_(2) has the largest brittleness.In addition,the Debye temperature calculation results of six kinds of mechanical stable phases show that the covalent bond strength of Cu_(10) Zr_(7) is the highest,while that of CuZr is the lowest.