Thermodynamic assessments of the Fe-Y and Ni-Sc systems

Abstract

The present study concerns the optimization of the Fe-Y and Ni-Sc systems by the help of the CALPHAD (CALculation of Phase Diagram) method, taking into account the available experimental results about phase equilibria and thermodynamic properties. The excess terms of the Gibbs energy of the solution phases (liquid, b.c.c., f.c.c. and h.c.p.) were assessed with the recent exponential temperature dependence of the interaction energies by Kaptay and compared with the linear dependence by Redlich-Kister. Furthermore, the computer program Thermo-Calc allows to obtain estimated data for experimentally undetermined thermodynamic properties and to compare the computed phase diagrams with those already published.