Critical Systematic Evaluation and Thermodynamic Optimization of the Fe-RE System: RE = Gd, Tb, Dy, Ho, Er, Tm, Lu, and Y

Abstract

As the second part of the thermodynamic study of binary Fe-RE system, critical evaluations and optimizations of all available phase diagrams and thermodynamic data for the Fe-heavy RE (heavy RE = Gd, Tb, Dy, Ho, Er, Tm, Lu, and Y) systems were conducted to obtain reliable thermodynamic functions of all the phases in the systems. In the thermodynamic modeling of the heavy RE systems, systematic variations in the phase diagrams and thermodynamic properties such as the enthalpy of mixing in the liquid state and enthalpy of formation of solid compounds with the atomic number of lanthanide series were observed. These systematic trends were incorporated in the optimization of the Fe-heavy RE system to resolve inconsistencies between available experimental data and to estimate unknown thermodynamic properties. The systematic trends in thermodynamic properties of solid and liquid phases and phase diagram of the entire Fe-RE systems were summarized.