About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Hume-Rothery Symposium: Data-Driven Materials Discovery and Phase Stability
|
| Presentation Title |
Relationship Between Configurational and Vibrational Entropies of Mixing and Their Effects on Phase Diagrams |
| Author(s) |
Jiaqi Feng, Dale Gaines II, Tzu-chen Liu, Nathan Smith, Christopher M. Wolverton |
| On-Site Speaker (Planned) |
Jiaqi Feng |
| Abstract Scope |
First-principles predictions of alloy phase stability typically only account for configurational entropy using the ideal random-mixing approximation. Vibrational entropy is increasingly recognized as an important additional contribution, but its effect has mostly been examined in individual systems rather than compared systematically across a broad set of alloys. Here, we use density functional theory and harmonic phonon calculations to evaluate configurational and vibrational free energies of mixing across ten binary alloys. Including vibrational entropy shifts predicted miscibility-gap temperatures relative to configurational-entropy-only estimates and generally improves agreement with experiment. The magnitude of this shift correlates with lattice mismatch, consistent with a bond-stiffness interpretation of vibrational entropy of mixing. However, mixing enthalpy and lattice mismatch alone do not reliably predict vibrational entropy across the dataset, suggesting that other chemical and structural factors also contribute. These results highlight both the importance of vibrational contributions and their current predictive limitations in first-principles alloy phase-diagram calculations. |
| Proceedings Inclusion? |
Planned: |