First-principle investigation of the stability and mechanical properties of the binder phase B(B=Co and Ni) with the maximum solubility of the transition-group elements M(M=V, Ti, Ta, Mo, W and Cr)

The superior binder phases are essential in maintaining the performance of cemented carbide. The stability and mechanical properties of the binder phases B(B=Co and Ni) which the transition-group elements M (M=V, Ti, Ta, Cr, Mo, and W) maximumly dissolve in are investigated by the first-principles calculation based on the density functional theory (DFT). The lattice constants of binder phases B increase when transition-group elements M dissolve in, and all B-M except for Ni-Cr binary solid solutions are thermodynamic stable. The dissolving of M can enhance the bulk modulus of B, and the shear modulus and Young’s modulus of Ni. Particularly, the dissolution of W, or Ta possess notable effect on the bulk modulus, shear modulus and Young’s modulus of B. Moreover, the dissolution of M makes the brittle Co the ductile material, retaining the ductility mode of Ni. Meanwhile, the elastic anisotropies are studied by calculating varied anisotropic indices and directional dependences of Young’s modulus(E) and shear modulus(G).