Documents disponibles écrits par cet auteur

Icosahedral clustering with medium-range order and local elastic properties of amorphous metals / M. Wakeda in Acta materialia, Vol. 58 N° 11 (Juin 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 11 (Juin 2010) . - pp. 3963–3969 Titre : Icosahedral clustering with medium-range order and local elastic properties of amorphous metals Type de document : texte imprimé Auteurs : M. Wakeda, Auteur ; Y. Shibutani, Auteur Année de publication : 2011 Article en page(s) : pp. 3963–3969 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Metallic  glasses  Medium-range  order  Elastic  behavior  Molecular  dynamics  simulations Résumé : The paper focuses on the relationship between icosahedral clustering with medium-range order in amorphous metals and local elastic properties. Using a Cu–Zr binary amorphous model constructed by rapid quenching in the framework of molecular dynamics simulations, Voronoi polyhedra analysis shows that the icosahedra are not randomly distributed in space, but form characteristic interpenetrating icosahedral clustering with medium-range order. It is shown that the center atoms of icosahedra within the highly developed interpenetrating icosahedral clusters have higher local elastic moduli than those of independently existing icosahedra and other polyhedra with lower coordination numbers. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410001746 [article] Icosahedral clustering with medium-range order and local elastic properties of amorphous metals [texte imprimé] / M. Wakeda, Auteur ; Y. Shibutani, Auteur . - 2011 . - pp. 3963–3969. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 11 (Juin 2010) . - pp. 3963–3969 Mots-clés : Metallic  glasses  Medium-range  order  Elastic  behavior  Molecular  dynamics  simulations Résumé : The paper focuses on the relationship between icosahedral clustering with medium-range order in amorphous metals and local elastic properties. Using a Cu–Zr binary amorphous model constructed by rapid quenching in the framework of molecular dynamics simulations, Voronoi polyhedra analysis shows that the icosahedra are not randomly distributed in space, but form characteristic interpenetrating icosahedral clustering with medium-range order. It is shown that the center atoms of icosahedra within the highly developed interpenetrating icosahedral clusters have higher local elastic moduli than those of independently existing icosahedra and other polyhedra with lower coordination numbers. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410001746

Nanoscale contact plasticity of crystalline metal / T. Tsuru in Acta materialia, Vol. 58 N° 8 (Mai 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 8 (Mai 2010) . - pp. 3096–3102 Titre : Nanoscale contact plasticity of crystalline metal : Experiment and analytical investigation via atomistic and discrete dislocation models Type de document : texte imprimé Auteurs : T. Tsuru, Auteur ; Y. Shibutani, Auteur ; Y. Kaji, Auteur Année de publication : 2011 Article en page(s) : pp. 3096–3102 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Nanoplasticity  Molecular  statics  Discrete  dislocation  mechanics  Boundary  element  method  Nanoindentation Résumé : Nanoscale incipient plastic deformation in crystalline metals occurs as the result of the collective motion of dislocations. It is known as “nanoplasticity” and is recognized as the elementary process of the macroscopic deformation. Abrupt increases in indent displacements called displacement bursts were observed in recent nanoindentation experiments; that is, the specific behavior for nanoplasticity. In the present study, experimental tests are first conducted to educe the unique nature of the nanoscale deformation. Subsequently, large-scale atomistic simulations are performed to predict the incipient plastic deformation and a new discrete dislocation model combined with the boundary element analysis is constructed to capture the collective motion of the dislocations. Our results suggest that the incipient plastic deformation requires much higher critical shear stress than the theoretical shear strength due to high compressive stress distribution beneath the indenter, and that the displacement burst is induced by surface rearrangement corresponding to hundreds of dislocation dipoles. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410000789 [article] Nanoscale contact plasticity of crystalline metal : Experiment and analytical investigation via atomistic and discrete dislocation models [texte imprimé] / T. Tsuru, Auteur ; Y. Shibutani, Auteur ; Y. Kaji, Auteur . - 2011 . - pp. 3096–3102. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 8 (Mai 2010) . - pp. 3096–3102 Mots-clés : Nanoplasticity  Molecular  statics  Discrete  dislocation  mechanics  Boundary  element  method  Nanoindentation Résumé : Nanoscale incipient plastic deformation in crystalline metals occurs as the result of the collective motion of dislocations. It is known as “nanoplasticity” and is recognized as the elementary process of the macroscopic deformation. Abrupt increases in indent displacements called displacement bursts were observed in recent nanoindentation experiments; that is, the specific behavior for nanoplasticity. In the present study, experimental tests are first conducted to educe the unique nature of the nanoscale deformation. Subsequently, large-scale atomistic simulations are performed to predict the incipient plastic deformation and a new discrete dislocation model combined with the boundary element analysis is constructed to capture the collective motion of the dislocations. Our results suggest that the incipient plastic deformation requires much higher critical shear stress than the theoretical shear strength due to high compressive stress distribution beneath the indenter, and that the displacement burst is induced by surface rearrangement corresponding to hundreds of dislocation dipoles. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410000789