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Theoretical study on hydrogen solubility and diffusivity in the γ-TiAl L10 structure

Connétable, Damien Theoretical study on hydrogen solubility and diffusivity in the γ-TiAl L10 structure. (2019) International Journal of Hydrogen Energy, 44 (23). 12215-12227. ISSN 0360-3199

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Official URL: https://doi.org/10.1016/j.ijhydene.2019.03.110

Abstract

The present work is a discussion on hydrogen solubility and diffusivity in the TiAl-L10 system using first-principles calculations. First, ground-state properties of the TiAl-L10 system are presented and discussed using elastic, phonon and thermal properties. They are compared with literature results. After having analyzed the geometry of L10 using the space-group theory, ten potential interstitial sites for hydrogen insertion were identified (among which the various octahedral and tetrahedral sites). After relaxation, only three configurations remained stable, but one site was significantly more stable than the others. The interactions between hydrogen and metal atoms are then described and analyzed by computing different quantities such as phonon properties, charge transfers, formation volumes and elastic dipoles. Diffusion mechanisms were then studied by analyzing the possible displacements at the atomic scale, and the diffusion coefficient of H atoms in TiAl was finally computed. Results how that H diffusion is strongly anisotropic.

Item Type:Article
HAL Id:hal-02134645
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Laboratory name:
Funders:
CALMIP - CALcul en MIdi Pyrénées (FRANCE)
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Deposited By: cirimat webmestre
Deposited On:15 May 2019 07:55

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