First-principles calculations of the electronic structure and phase stability of Ni-Mo alloys

Self-consistent local density electronic structure calculations have been carried out on various fee-based ground-state ordered superstructures of Ni1-xMox alloys spanning the entire concentration range. Using the tight-binding linear muffin-tin orbital (TB-LMTO) method, we have calculated the volume-dependent total ground-state energies, and hence the different equilibrium cohesive properties, as functions of the Mo concentration. Following the 'transferability prescription' of Andersen and co-workers, we have estimated the potential parameters of the constituent atoms as embedded in the alloy and compared these with the corresponding charge-self-consistent parameters for the intermetallic compounds. The ground-state stability profile has been obtained for the first time for this family of Ni-Mo compounds. Moreover, we have tested the applicability of the cluster expansion method (CEM) for parametrizing the cohesive energies to estimate the volume-dependent effective cluster interactions (ECIs) under the octahedron-tetrahedron cluster approximation.