About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Computational Thermodynamics and Kinetics
|
| Presentation Title |
An Efficient Method for Calculating Gibbs Free Energy and Thermal Expansion of Anharmonic Materials |
| Author(s) |
Kota Hashimoto, Tomonori Tanaka, Yoshihiro Gohda |
| On-Site Speaker (Planned) |
Kota Hashimoto |
| Abstract Scope |
Gibbs free energy is essential for understanding of material behavior, especially phase transitions and phase equilibria, where thermal expansion is a significant finite-temperature effect. The quasi-harmonic approximation (QHA) evaluates thermal expansion by varying volumes; however, it is inapplicable to anharmonic materials with imaginary phonons. Conversely, self-consistent phonon (SCPh) theory can incorporate anharmonic effects, but performing multiple SCPh calculations, like the QHA procedure, is computationally demanding. To address this issue, we propose an efficient approach, the volume integral of pressure (VIP) method, which evaluates the free energy change caused by thermal expansion using phonon frequencies and Grüneisen parameters obtained from first-principles phonon calculations at a single volume. The VIP method determines the equilibrium volume and Gibbs free energy at finite temperatures by calculating the pressure and its volume derivative. We demonstrate the accuracy and efficiency of this method for bcc Ti, a well-known anharmonic material, and tetragonal ZrO2. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Phase Transformations, Titanium |