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First-principles assessment of hydrogen absorption into FeAl and Fe3Si / Donald F. Johnson in Acta materialia, Vol. 58 N° 2 (Janvier 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 2 (Janvier 2010) . - pp. 638-648 Titre : First-principles assessment of hydrogen absorption into FeAl and Fe3Si : towards prevention of steel embrittlement Type de document : texte imprimé Auteurs : Donald F. Johnson, Auteur ; Emily A. Carter, Auteur Article en page(s) : pp. 638-648 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Density  functional  Kinetics  Hydrogen  absorption  Hydrogen  diffusion  Iron  alloys Index. décimale : 669 Métallurgie Résumé : We characterize the ability of two potential surface alloys, FeAl and Fe3Si, to prevent H incorporation into steel, with a view toward inhibiting steel embrittlement. Periodic density functional theory calculations within the generalized gradient approximation are used to evaluate H dissolution energetics and the kinetics of H diffusion into and through FeAl and Fe3Si. We predict increased dissolution endothermicities and diffusion barriers in both alloys compared to bulk Fe. Fe3Si is predicted to be the most effective at inhibiting H incorporation, with a 1.91 eV [0.97 eV] surface-to-subsurface diffusion barrier on the (1 1 0) surface [(1 0 0 surface)] and a 0.79 eV endothermicity to bulk dissolution, compared to a 1.02 eV [0.38 eV] barrier and 0.20 eV dissolution energy in pure Fe [37]. We therefore propose that a thin layer of Fe3Si may provide protection against H embrittlement of the underlying steel. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...] [article] First-principles assessment of hydrogen absorption into FeAl and Fe3Si : towards prevention of steel embrittlement [texte imprimé] / Donald F. Johnson, Auteur ; Emily A. Carter, Auteur . - pp. 638-648. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 2 (Janvier 2010) . - pp. 638-648 Mots-clés : Density  functional  Kinetics  Hydrogen  absorption  Hydrogen  diffusion  Iron  alloys Index. décimale : 669 Métallurgie Résumé : We characterize the ability of two potential surface alloys, FeAl and Fe3Si, to prevent H incorporation into steel, with a view toward inhibiting steel embrittlement. Periodic density functional theory calculations within the generalized gradient approximation are used to evaluate H dissolution energetics and the kinetics of H diffusion into and through FeAl and Fe3Si. We predict increased dissolution endothermicities and diffusion barriers in both alloys compared to bulk Fe. Fe3Si is predicted to be the most effective at inhibiting H incorporation, with a 1.91 eV [0.97 eV] surface-to-subsurface diffusion barrier on the (1 1 0) surface [(1 0 0 surface)] and a 0.79 eV endothermicity to bulk dissolution, compared to a 1.02 eV [0.38 eV] barrier and 0.20 eV dissolution energy in pure Fe [37]. We therefore propose that a thin layer of Fe3Si may provide protection against H embrittlement of the underlying steel. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...]