Thermodynamic modeling of the Th-In system using a hybrid approach combining CALPHAD and ab initio calculations
Year: 2026
Type: article
Abstract: The Thorium-Indium (Th-In) binary system has been thermodynamically assessed based on all available literature data, including phase equilibria information and thermodynamic properties. The assessment was performed using the CALPHAD (Calculation of Phase Diagrams) approach, implemented through the Thermo-Calc software package, in combination with ab initio density functional theory (DFT) calculations. The Gibbs free energies of the liquid phase were modeled using the subregular solution model with the Redlich–Kister equation, while those of the stoichiometric intermetallic compounds Th₂In, ThIn, Th₃In₅, and ThIn₃ were described using the two-sublattice model. In addition, the standard enthalpies of formation of the Th-In intermetallic compounds were determined from first-principles calculations within the DFT framework, using the WIEN2k code. The developed model reproduces the phase limits, solubility limits and enthalpies of formation in good agreement with the available data in the literature and the results obtained in this study. This approach improves the thermodynamic description and phase diagram of the Th–In system, especially in the thorium-rich region, which is difficult to characterize experimentally due to its high melting temperature. These results provide a reliable basis for future studies of thorium- and indium-based materials.
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,350
OpenAlex ID: W7213424323