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Discrete dislocation dynamics simulations of plasticity at small scales / Caizhi Zhou in Acta materialia, Vol. 58 N° 5 (Mars 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 5 (Mars 2010) . - pp. 1565–1577 Titre : Discrete dislocation dynamics simulations of plasticity at small scales Type de document : texte imprimé Auteurs : Caizhi Zhou, Auteur ; S. Bulent Biner, Auteur ; Richard LeSar, Auteur Année de publication : 2011 Article en page(s) : pp. 1565–1577 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Dislocation  dynamics  Size  effects  Plasticity Résumé : Discrete dislocation dynamics simulations in three dimensions have been used to examine the role of dislocation multiplication and mobility on the plasticity in small samples under uniaxial compression. To account for the effects of the free surfaces a boundary-element method, with a superposition technique, was employed. Cross-slip motion of the dislocation was also included, and found to be critical to the modeling of the dislocation behavior. To compare directly with recent experiments on micropillars, simulation samples at small volumes were created by cutting them from bulk three-dimensional simulations, leading to a range of initial dislocation structures. Application was made to single-crystal nickel samples. Comparison of the simulation results and the experiments are excellent, finding essentially identical behavior. Examination of details of the dislocation mechanism illuminates many features unique to small samples and points directly to the importance of both the surface forces and cross-slip in understanding small-scale plasticity. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409007678 [article] Discrete dislocation dynamics simulations of plasticity at small scales [texte imprimé] / Caizhi Zhou, Auteur ; S. Bulent Biner, Auteur ; Richard LeSar, Auteur . - 2011 . - pp. 1565–1577. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 5 (Mars 2010) . - pp. 1565–1577 Mots-clés : Dislocation  dynamics  Size  effects  Plasticity Résumé : Discrete dislocation dynamics simulations in three dimensions have been used to examine the role of dislocation multiplication and mobility on the plasticity in small samples under uniaxial compression. To account for the effects of the free surfaces a boundary-element method, with a superposition technique, was employed. Cross-slip motion of the dislocation was also included, and found to be critical to the modeling of the dislocation behavior. To compare directly with recent experiments on micropillars, simulation samples at small volumes were created by cutting them from bulk three-dimensional simulations, leading to a range of initial dislocation structures. Application was made to single-crystal nickel samples. Comparison of the simulation results and the experiments are excellent, finding essentially identical behavior. Examination of details of the dislocation mechanism illuminates many features unique to small samples and points directly to the importance of both the surface forces and cross-slip in understanding small-scale plasticity. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409007678