Gibbs energy modeling of Fe–Ta system by Calphad method assisted by experiments and ab initio calculations

In this work we report the Gibbs energy model parameters of equilibrium phases of Fe–Ta system obtained by the Calphad approach. In order to assist the Gibbs energy modeling new constitutional and enthalpy increment data were obtained by experiments. Further, the energy of formation of intermediate phases and the energy of mixing of bcc solid solution were calculated by ab initio method. These results were combined with selected experimental data from the literature in order to optimize the model parameters of the Gibbs energy functions. Calculated phase diagram and the thermochemical properties are in good agreement with the experimental results.