Titre :	Interaction elastique dislocation-interface dans des aux bicristaux elastiquement anisotropes de structure hexagonale
Type de document :	texte imprimé
Auteurs :	Aicha Ayadi, Auteur ; Omar Khalfallah, Directeur de thèse
Editeur :	جامعة الإخوة منتوري قسنطينة
Année de publication :	2015
Importance :	167 f.
Format :	30 cm.
Note générale :	2 copies imprimées disponibles
Langues :	Français (fre)
Catégories :	Français - Anglais Physique
Tags :	Interface  Dislocation  Force image  Contrainte de Peierls  système de glissement  structure hexagonale  élasticité anisotrope  Dislocations  Image Force  Peierls stress  slip system  hexagonal structure  elastic anisotropy إنخلاع  مستوى الانزلاق  بنية سداسية  قوة الصورة  طاقة التفاعل المرن  إجهاد Peierls تباين الخواص المرونية
Index. décimale :	530 Physique
Résumé :	The movement of a dislocation in interaction with an interface, in the absence of external stresses, is controlled by the balance of internal stresses. This assessment includes the friction force in the Peierls-Nabarro network stress and a force due to the anisotropy of the material called image force. We study the mobility of the perfect dislocation 1/3 <11-20> in the (0001) basal and prismatic (10-10) slip planes of the hexagonal structure. The dislocations are located in crystal (1) of a bicrystal among Zn, Be, Co, Hf, Ti, Zr, Cd, Y, Mg and Tl which are elastically anisotrope metals. They are parallel to the interface plane and are in elastic interaction with this interface and situated at a distance d therefrom. Each dislocation is characterized by its line direction and Burgers vector b. The interface is defined by its plane which is basal one for the two crystals and a null disorientation. The setting of the dislocation movement under the effect of the image force depends on the intensity of the elastic energy interaction of dislocation with interphase boundary and of the distance d where the dislocation is located. The setting in motion is effective if the intensity of the image force (Fi = -  E / d, E is the elastic interaction energy) is greater than the Peierls constraint. The dislocation is attracted or repelled upon the direction of image force. A critical distance, dc, is defined when image force is equal to the Peierls force. The dislocation is attracted to the interface when the crystal (2) is softer than the crystal (1), it is repelled when the crystal (2) is the hardest. The efficiency distance of image force increases with the absolute value of the difference in shear modulus of the materials constituting the bicrystal. The favored slip plane is selected by the c/a ratio of the crystal which is located dislocation. The result is in accordance with those of the behavior of dislocations in single crystals except for the cases crystals of the c/a ratio close to  (8/3) (Mg and Co).
Diplôme :	Doctorat en sciences
En ligne :	../theses/physique/AYA6802.pdf
Format de la ressource électronique :	pdf
Permalink :	index.php?lvl=notice_display&id=10055

Interaction elastique dislocation-interface dans des aux bicristaux elastiquement anisotropes de structure hexagonale [texte imprimé] / Aicha Ayadi, Auteur ; Omar Khalfallah, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2015 . - 167 f. ; 30 cm.
2 copies imprimées disponibles

Langues : Français (fre)

Catégories :	Français - Anglais Physique
Tags :	Interface  Dislocation  Force image  Contrainte de Peierls  système de glissement  structure hexagonale  élasticité anisotrope  Dislocations  Image Force  Peierls stress  slip system  hexagonal structure  elastic anisotropy إنخلاع  مستوى الانزلاق  بنية سداسية  قوة الصورة  طاقة التفاعل المرن  إجهاد Peierls تباين الخواص المرونية
Index. décimale :	530 Physique
Résumé :	The movement of a dislocation in interaction with an interface, in the absence of external stresses, is controlled by the balance of internal stresses. This assessment includes the friction force in the Peierls-Nabarro network stress and a force due to the anisotropy of the material called image force. We study the mobility of the perfect dislocation 1/3 <11-20> in the (0001) basal and prismatic (10-10) slip planes of the hexagonal structure. The dislocations are located in crystal (1) of a bicrystal among Zn, Be, Co, Hf, Ti, Zr, Cd, Y, Mg and Tl which are elastically anisotrope metals. They are parallel to the interface plane and are in elastic interaction with this interface and situated at a distance d therefrom. Each dislocation is characterized by its line direction and Burgers vector b. The interface is defined by its plane which is basal one for the two crystals and a null disorientation. The setting of the dislocation movement under the effect of the image force depends on the intensity of the elastic energy interaction of dislocation with interphase boundary and of the distance d where the dislocation is located. The setting in motion is effective if the intensity of the image force (Fi = -  E / d, E is the elastic interaction energy) is greater than the Peierls constraint. The dislocation is attracted or repelled upon the direction of image force. A critical distance, dc, is defined when image force is equal to the Peierls force. The dislocation is attracted to the interface when the crystal (2) is softer than the crystal (1), it is repelled when the crystal (2) is the hardest. The efficiency distance of image force increases with the absolute value of the difference in shear modulus of the materials constituting the bicrystal. The favored slip plane is selected by the c/a ratio of the crystal which is located dislocation. The result is in accordance with those of the behavior of dislocations in single crystals except for the cases crystals of the c/a ratio close to  (8/3) (Mg and Co).
Diplôme :	Doctorat en sciences
En ligne :	../theses/physique/AYA6802.pdf
Format de la ressource électronique :	pdf
Permalink :	index.php?lvl=notice_display&id=10055