Regensburg 2025 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 37: Functional and Complex Materials

MM 37.3: Talk

Friday, March 21, 2025, 12:30–12:45, H22

Entropy Decoupling in Vacancy Formation of BCC High-Entropy Alloys — •Xiang Xu, Xi Zhang, and Blazej Grabowski — University of Stuttgart, Stuttgart, Germany

The temperature-dependent vacancy formation energies in MoTaNbW systems have been calculated using a machine-learning-based interatomic potential that accurately captures the simultaneous effects of configurational and vibrational entropies, along with their coupling. Our results indicate that at elevated temperatures, careful treatment of the chemical potential is essential. We computed the distributions of vacancy formation energies up to the melting point, explicitly accounting for anharmonic vibrational effects. The findings demonstrate that, in this system, the local atomic environment around a vacancy exerts minimal influence on the vibrational entropy contributions.

Keywords: High entropy alloys; Vacancy formation energy; Machine-learning interatomic potentials; Configurational entropy; Vibrational entropy