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Plastic deformation of nanocrystalline aluminum at high temperatures and strain rate / A.P. Gerlich in Acta materialia, Vol. 58 N° 6 (Avril 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 6 (Avril 2010) . - pp. 2176–2185 Titre : Plastic deformation of nanocrystalline aluminum at high temperatures and strain rate Type de document : texte imprimé Auteurs : A.P. Gerlich, Auteur ; L. Yue, Auteur ; P.F. Mendez, Auteur Année de publication : 2011 Article en page(s) : pp. 2176–2185 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Nanocrystalline  materials  Plastic  deformation  High  temperature  Molecular  dynamics Résumé : The deformation of nanocrystalline aluminum was studied using molecular dynamics simulation at homologous temperatures up to 0.97. The microstructures and stress–strain response were examined in a polycrystalline and bicrystal configuration. The activation energies for dislocation-based deformation as well as grain boundary sliding and migration were quantified by fitting simulation data to temperature using an Arrhenius relation. The activation energy for the flow stress response suggests that deformation is largely accommodated by sliding and migration of grain boundaries. This is in agreement with simulated microstructures, indicating a negligible degree of dislocation interaction within each grain, and microstructural observations from high strain rate processes are also consistent with this result. A steady-state grain size is maintained in the recrystallized structure following yielding due to boundary migration and grain rotation mechanisms, rather than by diffusion-based dislocation climb. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409008374 [article] Plastic deformation of nanocrystalline aluminum at high temperatures and strain rate [texte imprimé] / A.P. Gerlich, Auteur ; L. Yue, Auteur ; P.F. Mendez, Auteur . - 2011 . - pp. 2176–2185. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 6 (Avril 2010) . - pp. 2176–2185 Mots-clés : Nanocrystalline  materials  Plastic  deformation  High  temperature  Molecular  dynamics Résumé : The deformation of nanocrystalline aluminum was studied using molecular dynamics simulation at homologous temperatures up to 0.97. The microstructures and stress–strain response were examined in a polycrystalline and bicrystal configuration. The activation energies for dislocation-based deformation as well as grain boundary sliding and migration were quantified by fitting simulation data to temperature using an Arrhenius relation. The activation energy for the flow stress response suggests that deformation is largely accommodated by sliding and migration of grain boundaries. This is in agreement with simulated microstructures, indicating a negligible degree of dislocation interaction within each grain, and microstructural observations from high strain rate processes are also consistent with this result. A steady-state grain size is maintained in the recrystallized structure following yielding due to boundary migration and grain rotation mechanisms, rather than by diffusion-based dislocation climb. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409008374