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Aluminum Σ3 grain boundary sliding enhanced by vacancy diffusion / Ningning Du in Acta materialia, Vol. 58 N° 12 (Juillet 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 12 (Juillet 2010) . - pp. 4245–4252 Titre : Aluminum Σ3 grain boundary sliding enhanced by vacancy diffusion Type de document : texte imprimé Auteurs : Ningning Du, Auteur ; Yue Qi, Auteur ; Paul E. Krajewski, Auteur Année de publication : 2011 Article en page(s) : pp. 4245–4252 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Molecular  dynamics  Grain  boundary  sliding  Aluminum  Superplasticity  Grain  boundary  structure Résumé : Grain boundary sliding is an important deformation mechanism for elevated temperature forming processes. Molecular dynamics simulations are used to investigate the effect of vacancies in the grain boundary vicinity on the sliding of Al bi-crystals at 750 K. The threshold stress for grain boundary sliding was computed for a variety of grain boundaries with different structures and energies. These structures included one symmetrical tilt grain boundary and five asymmetrical tilt grain boundaries. Without vacancies, low energy Σ3 grain boundaries exhibited significantly less sliding than other high energy grain boundaries. The addition of vacancies to Σ3 grain boundaries decreased the threshold stress for grain boundary sliding by increasing the grain boundary diffusivity. A higher concentration of vacancies enhanced this effect. The influence of vacancies on grain boundary diffusivity and grain boundary sliding was negligible for high energy grain boundaries, due to the already high atom mobility in these boundaries. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410002326 [article] Aluminum Σ3 grain boundary sliding enhanced by vacancy diffusion [texte imprimé] / Ningning Du, Auteur ; Yue Qi, Auteur ; Paul E. Krajewski, Auteur . - 2011 . - pp. 4245–4252. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 12 (Juillet 2010) . - pp. 4245–4252 Mots-clés : Molecular  dynamics  Grain  boundary  sliding  Aluminum  Superplasticity  Grain  boundary  structure Résumé : Grain boundary sliding is an important deformation mechanism for elevated temperature forming processes. Molecular dynamics simulations are used to investigate the effect of vacancies in the grain boundary vicinity on the sliding of Al bi-crystals at 750 K. The threshold stress for grain boundary sliding was computed for a variety of grain boundaries with different structures and energies. These structures included one symmetrical tilt grain boundary and five asymmetrical tilt grain boundaries. Without vacancies, low energy Σ3 grain boundaries exhibited significantly less sliding than other high energy grain boundaries. The addition of vacancies to Σ3 grain boundaries decreased the threshold stress for grain boundary sliding by increasing the grain boundary diffusivity. A higher concentration of vacancies enhanced this effect. The influence of vacancies on grain boundary diffusivity and grain boundary sliding was negligible for high energy grain boundaries, due to the already high atom mobility in these boundaries. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410002326