Calphad-type assessment of the Fe–Nb–Ni ternary system

Abstract

This paper presents a Calphad-type thermodynamic database for the Fe–Nb–Ni system. The stable phases in this ternary system are liquid, fcc_A1, bcc_A2, C14 Laves, D0 a , D8 5 and L1 2_fcc but we took also into account the C15 Laves and the metastable D0 22 phase because of their engineering interest. Available optimizations of the unary and binary systems were selected from the literature with the constraint that the Gibbs energy descriptions must be compatible. The only amendment needed to the selected assessments concerned the parameters for the D8 5 in the Fe–Nb system. In addition, ab-initio calculations have been performed using the VASP in order to help with estimating enthalpies of formation of some binary end members of the intermetallic compounds. The optimization of the Fe–Nb–Ni ternary system was performed using mostly experimental data available in the literature.