First-Principles Study Of The Physical Properties Of Several Typical Binary Compounds

Due to the dodecaboride and B2 structure DyCu alloys have magnificent physical properties,researchers consider them to be a pretty satisfactory industrial material.However,few systematic study on the physical properties of B₁₂M?M=Th,U,Np,Pu?and B2 structure DyCu alloys has been carried out,which seriously delays their application in industry.In this paper,we have investigated the phase stability,elasticity,anisotropy,kinetic stability,and thermodynamic properties of B₁₂M?M=Th,U,Np,Pu?dodecaboride by the first-principles.The optimized structure constant is consistent with the experimental result.The ratio of formation enthalpy and pressure V/V₀ demonstrates that B₁₂M has good phase stability.The elastic parameters and the modulus of elasticity of B₁₂M show that it is a brittle superhard material.Futhermore,B₁₂M possesses anisotropy proved by the anisotropy factors of B₁₂M as well as three and two-dimensional projections of Young's modulus,while the degree is relatively small.The relationship between the anisotropy of sound speed and the minimum thermal conductivity,thermodynamic quantities and temperature are calculated and discussed.The lattice dynamics properties of the four B₁₂M satisfy dynamic stability conditions.Simultaneously,the result anticipates the preferred position and mechanical properties of transition metal elements in B2 structure DyCu alloys by the first-principles.The formation enthalpy of ternary alloys displays that most of transition metal elements tend to occupy the Cu site,then form Dy₈Cu₇M intermetallic compounds.According to calculation results of elastic modulus,Dy₇Cu₈V has the highest ductility,and Dy₇Cu8Hf owns relatively high shear modulus and Young's modulus.The anisotropic factor,Young's modulus,3D and 2D plots predict that the DyCuM compounds belong to anisotropic materials,but the value of anisotropic is small.