Thermodynamic Modeling of the Re-Ru, Ru-W and Re-Ru-W Systems

Phase equilibria and thermodynamic properties of the Ni-based superalloys are fundamental to design novel Ni-based superalloys with outstanding high temperature resistance properties. In order to develop the thermodynamic database of multi-component Ni-based superalloys with the elements Re, Ru and W, thermodynamic assessments of the Re-Ru, Ru-W and Re-Ru-W systems over the whole composition range were carried out using the CALPHAD (CALculation of PHAse Diagrams) method based on the available experimental phase equilibria data reported in the literature. The substitutional solution model was used to describe the solution phases including liquid, (Re), (Ru) and (W). The intermetallic compounds σ and χ were described by the sublattice models (Re,Ru,W)10(W)4(Re,Ru,W)16 and (Re,Ru)24(Re,W)10(Re,Ru,W)24, respectively. A set of self-consistent thermodynamic parameters for the Re-Ru, Ru-W and Re-Ru-W systems was obtained. Comparisons between the calculated results and experimental data show that most of the reliable experimental data can be reproduced by the present thermodynamic modeling.