Thermodynamic Evaluation of the Fe-Pr Binary System

Abstract

The Fe–Pr binary system was thermodynamic evaluation by means of the CALPHAD method based on phase diagram experimental data from the literature and a few values of the mixing enthalpy in the liquid phase obtained by the Miedema theory technique. Each of the selected data values is given a certain weight, which is chosen and adjusted based on the thermodynamic data and diagram phase data. A consistent thermodynamic description of the Fe–Pr binary system is presented: only one intermediate compound, Fe17Pr2, is stable in the system and forms peritectically at 1371K. An eutectic reaction L↔Pr+ Fe17Pr2 occurs at 939K and the eutectic liquid contains 82 at% Pr, five solid solution phases (Fe-rich αFe, γFe and δFe, Pr-rich αPr and βPr) and the liquid solution phase were considered in the evaluation. The intermediate phase was treated as stoichiometric compound, the solid solutions as ideal and the liquid solution phase by the Redlich–Kister formalism. The calculated phase diagram and thermodynamic properties are in good agreement with available experimental data.