Titre :	Calcul de l'énergie de ségrégation superficielle dans les alliages de métaux C.F.C. 5 Ni , Rh; Ir; Pd; Pt)
Type de document :	texte imprimé
Auteurs :	Sihem Menassel ; Univ. de Constantine, Éditeur scientifique ; Omar Khalfallah, Directeur de thèse
Année de publication :	2007
Importance :	65 f.
Note générale :	01 Disponible à la salle de recherche 02 Disponibles au magazin de la B.U.C. 01 CD
Langues :	Français (fre)
Catégories :	Français - Anglais Physique
Tags :	Simulation  Surface  Ségrégation  Dynamique moléculaire  Potentiel RGL
Index. décimale :	530 Physique
Résumé :	The properties of metals and alloys depend on the structure, on the chemical composition and the defects. The phenomenon of segregation in both surface and to the grain boundaries made the object of intense theoretical and experimental research. The modelling of the existence of superficial segregation was the more developed. It reveals three driving forces: size effect, excess cohesion effect and alloy effect. The present study examins the calculations of the segregation energy, using molecular dynamics simulation for binary metallic alloys of structure CFC with Nickel in the limit of the infinitely dilute solution. The interatomic interactions are modelized using an empirical N - body potential of Finnis - Sinclair type developed to the third neighbours. The calculations results of the segregation energies show that the segregation is localized mainly on the first two plans. Whereas the plan of the surface, it is favorable for the direct alloys Ni(Pd) and Ni(Pt) but unfavorable for Ni(Ir) and Ni(Rh).The reconstruction of the segregation energy by the contributions of the effects of size and excess of cohesion, is not satisfactory. The contribution of the alloy effect remains weak and does not improve significantly the reconstruction of the segregation energy for the direct systems, except for Ni(Pd)..
Diplôme :	Magistère
En ligne :	../theses/physique/MEN4925.pdf
Permalink :	index.php?lvl=notice_display&id=3524

Calcul de l'énergie de ségrégation superficielle dans les alliages de métaux C.F.C. 5 Ni , Rh; Ir; Pd; Pt) [texte imprimé] / Sihem Menassel ; Univ. de Constantine, Éditeur scientifique ; Omar Khalfallah, Directeur de thèse . - 2007 . - 65 f.
01 Disponible à la salle de recherche 02 Disponibles au magazin de la B.U.C. 01 CD
Langues : Français (fre)

Catégories :	Français - Anglais Physique
Tags :	Simulation  Surface  Ségrégation  Dynamique moléculaire  Potentiel RGL
Index. décimale :	530 Physique
Résumé :	The properties of metals and alloys depend on the structure, on the chemical composition and the defects. The phenomenon of segregation in both surface and to the grain boundaries made the object of intense theoretical and experimental research. The modelling of the existence of superficial segregation was the more developed. It reveals three driving forces: size effect, excess cohesion effect and alloy effect. The present study examins the calculations of the segregation energy, using molecular dynamics simulation for binary metallic alloys of structure CFC with Nickel in the limit of the infinitely dilute solution. The interatomic interactions are modelized using an empirical N - body potential of Finnis - Sinclair type developed to the third neighbours. The calculations results of the segregation energies show that the segregation is localized mainly on the first two plans. Whereas the plan of the surface, it is favorable for the direct alloys Ni(Pd) and Ni(Pt) but unfavorable for Ni(Ir) and Ni(Rh).The reconstruction of the segregation energy by the contributions of the effects of size and excess of cohesion, is not satisfactory. The contribution of the alloy effect remains weak and does not improve significantly the reconstruction of the segregation energy for the direct systems, except for Ni(Pd)..
Diplôme :	Magistère
En ligne :	../theses/physique/MEN4925.pdf
Permalink :	index.php?lvl=notice_display&id=3524