Thermodynamic calculation of the phase diagram of the Co–Nb–Ta system

Abstract A thermodynamic description of the ternary system Co–Nb–Ta is obtained by combining the descriptions of the lower-order systems according to the CALPHAD method. The thermodynamic data set for the binary Co–Nb system is taken from [1], where a new thermodynamic model for the μ-phase was introduced. The μ-phase appears in several transition metal systems, including Co–Ta. The model is applied to the Co–Ta system and extended to the ternary Co–Nb–Ta system. The thermodynamic descriptions of the systems Co–Ta, Nb–Ta and Co–Nb–Ta are reported in the present work.