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Plastic anisotropy of γ-TiAl revealed by axisymmetric indentation / C. Zambaldi in Acta materialia, Vol. 58 N° 9 (Mai 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 9 (Mai 2010) . - pp. 3516–3530 Titre : Plastic anisotropy of γ-TiAl revealed by axisymmetric indentation Type de document : texte imprimé Auteurs : C. Zambaldi, Auteur ; D. Raabe, Auteur Année de publication : 2011 Article en page(s) : pp. 3516–3530 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Instrumented  indentation  EBSD  AFM  Crystal  plasticity  AuCu  prototype Résumé : Single crystals of γ-TiAl cannot be grown in the near-stoichiometric compositions that are present inside two-phase γ/α2-microstructures with attractive mechanical properties. Therefore, the single-crystal constitutive behavior of γ-TiAl was studied by nanoindentation experiments in single-phase regions of these γ/α2-microstructures. The experiments were characterized by orientation microscopy and atomic force microscopy to quantify the orientation-dependent mechanical response during nanoindentation. Further, they were analyzed by a three-dimensional crystal plasticity finite element model that incorporated the deformation behavior of γ-TiAl. The spatially resolved activation of competing deformation mechanisms during indentation was used to assess their relative strengths. A convention was defined to unambiguously relate any indentation axis to a crystallographic orientation. Experiments and simulations were combined to study the orientation-dependent surface pile-up. The characteristic pile-up topographies were simulated throughout the unit triangle of γ-TiAl and represented graphically in the newly introduced inverse pole figure of pile-up patterns. Through this approach, easy activation of ordinary dislocation glide in stoichiometric γ-TiAl was confirmed independently from dislocation observation by transmission electron microscopy. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410001114 [article] Plastic anisotropy of γ-TiAl revealed by axisymmetric indentation [texte imprimé] / C. Zambaldi, Auteur ; D. Raabe, Auteur . - 2011 . - pp. 3516–3530. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 9 (Mai 2010) . - pp. 3516–3530 Mots-clés : Instrumented  indentation  EBSD  AFM  Crystal  plasticity  AuCu  prototype Résumé : Single crystals of γ-TiAl cannot be grown in the near-stoichiometric compositions that are present inside two-phase γ/α2-microstructures with attractive mechanical properties. Therefore, the single-crystal constitutive behavior of γ-TiAl was studied by nanoindentation experiments in single-phase regions of these γ/α2-microstructures. The experiments were characterized by orientation microscopy and atomic force microscopy to quantify the orientation-dependent mechanical response during nanoindentation. Further, they were analyzed by a three-dimensional crystal plasticity finite element model that incorporated the deformation behavior of γ-TiAl. The spatially resolved activation of competing deformation mechanisms during indentation was used to assess their relative strengths. A convention was defined to unambiguously relate any indentation axis to a crystallographic orientation. Experiments and simulations were combined to study the orientation-dependent surface pile-up. The characteristic pile-up topographies were simulated throughout the unit triangle of γ-TiAl and represented graphically in the newly introduced inverse pole figure of pile-up patterns. Through this approach, easy activation of ordinary dislocation glide in stoichiometric γ-TiAl was confirmed independently from dislocation observation by transmission electron microscopy. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410001114