Site preference and alloying effect of tungsten in the μ phase of Co₇Mo₆

The electronic structures of the μ phase of Co7Mo6 were investigated by means of first-principles calculation based on the density functional theory. The calculated equilibrium lattice parameters of Co7Mo6 are in good agreement with the experimental results. The results of calculation reveal that the addition of tungsten (W) promotes the stability of the μ phase of Co7Mo6 and W tends to participate in its formation. Through analysing the calculated electronic structure (partial density of states and charge density difference), it can be noted that a strong interaction exists due to d–d hybridization. Also, the majority of the atoms may contribute their valence electrons to the formation of metallic bonds in binary and ternary systems. Furthermore, the calculated results show that the doped W atom prefers to occupy the Co site in Co7Mo6 μ phase.