A thermodynamic evaluation of the C-Cr-Nb system

Based on critical evaluation of the literature data, the C-Cr-Nb system has been reviewed and assessed by means of the CALPHAD technique. A reassessment of the Cr-Nb system was conducted in order to better reproduce the invariant reactions in the C-Cr-Nb system. A set of self-consistent thermodynamic parameters for the Gibbs energies of individual phases in the C-Cr-Nb system was then obtained by taking into account the literature data including isothermal sections, liquidus, solidus and invariant reactions. Comprehensive comparisons between the calculated and measured phase diagrams show that all the reliable experimental information is satisfactorily accounted for by the present thermodynamic description. The liquidus projection and reaction scheme over the whole composition and temperature ranges are presented.