Computational Investigation On The Thermodynamic And Mechanical Properties Of Key Binary Systems In Cu Alloys

Abstract:Cu alloys perform wonderfully in hardness, strength, cutting resistance, corrosion-resistance and wear-resistance. They are widely used in the fields of electric engineering, transportation, light industry, metallurgical industry, building materials etc. It is helpful to design new Cu alloys by decribing thermodynamic and mechanical properties accurately The object of present research is about common binary Cu alloys. Based on the first-pinciple calculations, the ground state properties, thermodynamic properites and mechanical properties of binary Cu compounds are systematically predicted. Also the mechanical properties and stacking fault energy of dilute Cu-X solutions are presented. A brief summary of this work is as follows:(1) By fitting the four-parameter equation of state, the equilibrium properties of Cu-X compounds including crystal structure, enthalpy of formation and density of state were investigated.(2) Based on the quasi-harmonic approximation and Debye model, the thermodynamic properties of these pure alloying elements X and Cu-X compounds in finite temperature are systematically investigated.(3) With the stress-strain method, the mechanical properties of Cu-X compounds were predicted. The elastic constants of Cu-X compounds were calculated firstly. The mechanical stability of these crystal structures were verified by corresponding standard. From the elastic constants the elastic properites were calculated The Cu-X compounds were divided into ductile and brittle groups accroding to B/G ratio.(4) In the method of the stress-strain, the mechanical properties of Cu-X dilute solutions were presented. Based on the acquired elastic constants, elastic modulus, B/G ratio and anisotropy ratio were calculated.(5) With the method of alias shear, the solid-solution strengthening in dilute Cu-X alloys were researched. The generalized stacking fault energies of pure Cu and dilute Cu-x alloys with alloying elements were calculated. Then we analysed the change of the stacking fault energy with respect to different alloying elements or different content of the same elemtent.