Séminaire de Yann Charles

Y. Charles, J. Mougenot, M. Gaspérini, N. Iskounen

"Hydrogen has received since the last decade a strong focus as a possible energy carrier, connected with international and national programs, dedicated to the acceleration of the production mean, or H2 transport and storage (1). Hydrogen isotopes are also involved in the Fusion processes, a promising long term energy source, currently studied in experimental tokamak as ITER (2, 3). However, hydrogen embrittlement phenomena can significantly degrade mechanical properties of materials and lead to premature failure. These phenomena result from material-hydrogen interactions at various scales, ranging from the atomic to the macroscopic scale. In metallic materials, once absorbed in surface, bulk diffusion through lattice interstitial sites and trapping at microstructural defects (vacancies, dislocations, grain boundaries…) or hydride formation are the main mechanisms involved in hydrogen transport, with various kinetics and coupling effects (4). Accounting for these interactions in finite element modeling to solve various initial boundary conditions problems is a stimulating challenge to predict and prevent hydrogen embrittlement in components.
In this context, the equations governing environmentally assisted-hydrogen transport and trapping are presented, along with the numerical strategy used to solve strongly coupled chemo-thermomechanical problems in Abaqus Finite Element software.
Several extensions of the pioneering works accounting both for stress-assisted diffusion and dislocation trapping (5, 6), were developed, including transient (multi)trapping (7–9), hydrogen dragging by mobile traps (9, 10), Soret effet (11)…
Special attention is paid on scale transitions from the discrete to continuum mechanics, using constitutive laws based on low-scale results. Two main aspects of the current developments (12, 13) are focused on: on the one hand, the coupling between hydrogen transport and crystalline plasticity models, and, on the other hand, the hydrogen-induced blistering. Limitations of the models and open questions are discussed.

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6. A. H. M. Krom, R. W. J. Koers, A. D. Bakker, J Mech Phys Solids. 47, 971–992 (1999).
7. S. Benannoune, Y. Charles, J. Mougenot, M. Gaspérini, Int J Hydrog Energy. 43, 9083–9093 (2018).
8. Y. Charles, J. Mougenot, M. Gaspérini, Int J Hydrog Energy. 46, 10995–11003 (2021).
9. S. Chroeun et al., Met. Mater. Trans. A. 56, 1–18 (2025).
10. Y. Charles, J. Mougenot, M. Gaspérini, Int J Hydrog Energy. 47, 13746–13761 (2022).
11. M. A. Rahman, M. Z. Saghir, Int. J. Heat Mass Transf. 73, 693–705 (2014).
12. S. Chroeun, Y. Charles, M. Gaspérini, J. Mougenot, Submitted to Int J Hydrogen Energy (2026).
13. M. D. Nguyen et al., Computational Materials Science, accepted (2026)."