Thermodynamic assessment of the Co-Mo-Ni and Mo-Ni-W ternary systems

The Co-Mo-Ni and Mo-Ni-W ternary systems were assessed by means of the CALPHAD approach. All of the experimental phase diagram and thermodynamic data available from the literature were critically reviewed. The liquid, (γCo), (Ni), (Mo), (W) and (εCo) were modeled as substitutional solution phases, while the intermetallic compounds including Mo0.2Co0.8, Mo6Co7, Sigma, Co3Mo, MoNi, MoNi3, (Mo,W)Ni4, WNi and W2Ni were described by using corresponding sublattice models. The (Mo,W)Ni4 is a continuous line compound based on MoNi4 and WNi4 phases. The modeling of Co-Mo-Ni and Mo-Ni-W systems covers the entire composition and temperature ranges, and a set of self-consistent thermodynamic parameters for the Co-Mo-Ni and Mo-Ni-W systems was obtained. Comprehensive comparisons between the calculated and reported experimental phase diagram and thermodynamic data show that the experimental information is satisfactorily accounted for by the present thermodynamic description. The liquidus projections and reaction schemes of the Co-Mo-Ni and Mo-Ni-W systems were also generated by using the present thermodynamic parameters.