Plastic deformation of wadsleyite / Arnaud Metsue in Acta materialia, Vol. 58 N° 5 (Mars 2010)  

Public ISBD [article]  inActa materialia > Vol. 58 N° 5 (Mars 2010) . - pp. 1467–1478 Titre : Plastic deformation of wadsleyite : IV Dislocation core modelling based on the Peierls–Nabarro–Galerkin model Type de document : texte imprimé Auteurs : Arnaud Metsue, Auteur ; Philippe Carrez, Auteur ; Christophe Denoual, Auteur Année de publication : 2011 Article en page(s) : pp. 1467–1478 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Wadsleyite Dislocations Modelling Peierls–Nabarro Element-free Galerkin Résumé : In this paper, we determine dislocation core structures and Peierls stresses of wadsleyite, a high-pressure mineral present in the Earth mantle. We use a Peierls–Nabarro model combined with a finite-element method in which we introduce two-dimensional generalized stacking fault energies. Several potential slip planes of wadsleyite are considered. The results show that dislocations in this mineral can exhibit complex dislocation cores with linear or non-collinear dissociation and even three-dimensional dislocation cores. The calculation of the Peierls stresses gives information on the potential activity of slip systems governing the plasticity of wadsleyite. Our study confirms experimental observations that ½〈1 1 1〉{1 0 1} is the easiest slip system in this structure at high-pressure and that [1 0 0](0 1 0) is the second easiest. Both these easily slip systems have dislocations that dissociate into collinear partial dislocations. In contrast [0 1 0] dislocations with very large Burgers vector (11.2 Å) are stabilized by complex dissociations involving four partial dislocations. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409007502 [article] Plastic deformation of wadsleyite : IV Dislocation core modelling based on the Peierls–Nabarro–Galerkin model [texte imprimé] / Arnaud Metsue, Auteur ; Philippe Carrez, Auteur ; Christophe Denoual, Auteur . - 2011 . - pp. 1467–1478. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 5 (Mars 2010) . - pp. 1467–1478 Mots-clés : Wadsleyite Dislocations Modelling Peierls–Nabarro Element-free Galerkin Résumé : In this paper, we determine dislocation core structures and Peierls stresses of wadsleyite, a high-pressure mineral present in the Earth mantle. We use a Peierls–Nabarro model combined with a finite-element method in which we introduce two-dimensional generalized stacking fault energies. Several potential slip planes of wadsleyite are considered. The results show that dislocations in this mineral can exhibit complex dislocation cores with linear or non-collinear dissociation and even three-dimensional dislocation cores. The calculation of the Peierls stresses gives information on the potential activity of slip systems governing the plasticity of wadsleyite. Our study confirms experimental observations that ½〈1 1 1〉{1 0 1} is the easiest slip system in this structure at high-pressure and that [1 0 0](0 1 0) is the second easiest. Both these easily slip systems have dislocations that dissociate into collinear partial dislocations. In contrast [0 1 0] dislocations with very large Burgers vector (11.2 Å) are stabilized by complex dissociations involving four partial dislocations. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409007502

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