Thermodynamic assessment of the Nb-Si-Mo system

Based on the experimental isothermal sections at 800, 1000, 1700 and 1800 °C and the liquidus projections from both the literature and the present measurements, the ternary NbSiMo system is thermodynamically assessed using the Calculation of Phase Diagram method (CALPHAD). The constituent MoSi binary system is reassessed according to its related binary experimental data. The sublattice model of the phase Nb₅Si₃ in the constituent NbSi binary system is modified as (Nb)_0.5(Nb,Si)_0.125(Nb, Si)_0.375, in order to give the solid phase β(Nb,Mo)5Si3 in the NbSiMo ternary system a better description. The parameters of the thermodynamic descriptions of the NbSiMo ternary system are optimized following the reported NbMo, the modified NbSi and the reassessed MoSi binary systems. The comparison between the calculated results and the experimental investigations shows that the present modeling can finely describe the experimental information of the NbSiMo ternary system.