Co_xB_y 合 金 力 学 性 能 、热 学 性 质 及电 子 性 质 的 第 一 性 原 理 研 究

Co_xB_y alloy with high hardness and high melting point has wide range of applications in many fields because of its stable chemical property，high strength，and good thermal stability. In this work，the thermodynamic and electrical properties of five Co_xB_y alloys（CoB，Co₂B，Co₃B，Co₂₃B₆ and Co₅B₁₆），were studied and compared based on a first-principles approach. The elastic constant and related mechanical property of the binary alloys were calculated by using the energy-strain method，and the thermodynamic properties such as the Debye temperature（Θ_D）and the coefficient of thermal expansion（α）within a finite temperature were calculated based on the quasi-simple harmonic Debye model. By comparing the mechanical parameters of the binary alloys，it is found that the comprehensive mechanical property of the CoB alloy is the best among the studied alloys；the state density mapping indicates that all five Co_xB_y alloys have good metallicity and electrical conductivity，and have some potential applications in the field of electrode materials. In Co₃B and Co₂₃B₆ alloys，there is a resonance peak between the d electron orbital of Co atom and the p electron orbital of B atom，indicating that there is a significant chemical bond between Co—B. The study complements the gap of thermomechanical property parameters of Co_xB_y binary alloys and provides a theoretical reference for the design and application of Co based or Co—B binary alloy materials.