Thermodynamic modeling of the Nb-rich corner in the Nb–Si–B system

Thermodynamic modeling of the Nb-rich region of the Nb–Si–B system has been carried out in this study using the CALPHAD approach, through which a thermodynamic description of the Nb–Si–B system was developed on the basis of thermodynamic models of the constituent binaries and critically reviewed ternary experimental data. T2, D88 and NbB had been found to have large homogeneity ranges in the ternary, and were therefore described by the sublattice models of Nb5(Si,B)3, (Nb)5(Si,B)3(B,Va) and Nb(B,Si), respectively, based on their crystal structures and homogeneity ranges. Isothermal sections, isopleths, liquidus projection as well as solidification paths were calculated accordingly from the currently obtained thermodynamic description of the Nb–Si–B system. The calculated results were compared favorably with the experimental data from literature.