Interaction dislocation – joints de grains dans l’Alumine Alpha.

Abstract

The interaction between matrix dislocations and grain boundaries is at the origin of many mechanical properties of polycrystals. Two types of stress transfer processes may occur: slip transmission and matrix dislocation accommodation in boundaries with diffusion. The accommodation mechanisms depend on intergranular structure and dopants. Our investigations done on the alumina-alpha bicrystals, which are in: the rhombohedral twin orientation and Y or Mg doped, and the twin orientation with (011 ̅5) boundary plane and La doped or undoped. The purpose of this study is to calculate the image force due to dislocationgrain boundary interaction and to determine the accommodation process of matrix dislocation during a creep, the deformation conditions (Temperature, Stress, Orientations,) are determined so as to activate two basal slip systems in each grain. * The elastic interaction energy between dislocation and grain boundary is calculated on the basis of the theory of the elasticity in anisotropic materials, and the image force is deduced. The interaction energies determined are represented by the draw iso-energy maps, the maps present no symmetry , the maximal extreme values of the image force is noted for Burgers vector