Elastic Interaction between Dislocation and Interface in Elastically Anisotropic Ceramic Bimaterials Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-AlN: Image Force Effect

Ayadi Aicha,Khalfallah Omar

doi:10.13189/ujme.2017.050403

Abstract

The Al2O3 and AlN materials are often used as electrical insulators (electronic substrates) also the case of pressure sensors where the aluminum nitride (AlN) is selected as the piezoelectric layer and the alumina (Al2O3) as a solid substrate insulating. This study aims to investigate the mobility of dislocations near the heterophase interface of bimaterials based alumina (Al2O3) under the effect of the image force, without the effect of temperature, deformation and external stress These dislocations having a Burgers vector b = 1/3 , they are located in Al2O3. The interface is defined by its plane parallel to the dislocation line and disorientation varies between 0 and 180。 around the axis . Usually, the image force calculated in the context of the anisotropic linear elasticity using Barnett and Lothe theory with Stroh formalism, Fi = ΔE / d, where ΔE is the elastic interaction energy. The results show that dislocation motion under the image force effect depends on the elastic and crystallographic properties of the materials constituting the bicrystals and even disorientation of the interface which has an effect on the intensity of the elastic interaction energy. The dislocations are repelled to the interface if the difference in shear modulus between the two materials is positive (Δμ= μ2 − μ1>0), they are attracted to the interface in the opposite case (Δμ= μ2 − μ1<0).

Highlights

Ceramic materials have a very important defect, which is their greater or less fragility
Several factors are related to image force, the boundary plane and disorientation, the dislocations characteristics, the different shear modulus of the materials constituting the bicrystals; and the distance of dislocation associated to the interphase boundaries
The objective of our work is the study of the setting in motion of the dislocations, near and parallel to an interphase boundary, under the effect of the image force in ceramic bicrystals Al2O3-aluminum nitride (AlN)

Summary

Introduction

Ceramic materials have a very important defect, which is their greater or less fragility. The elastic interactions between a specific defect and a dislocation and between dislocations have established the basis of mono-crystalline homophase behavior. Several factors are related to image force, the boundary plane and disorientation, the dislocations characteristics (direction and Burgers vector), the different shear modulus of the materials constituting the bicrystals; and the distance of dislocation associated to the interphase boundaries. [5] have dealt with the case of CFC structural materials and interactions between the matrix dislocations and grain boundaries during plastic deformation [6]. The objective of our work is the study of the setting in motion of the dislocations, near and parallel to an interphase boundary, under the effect of the image force in ceramic bicrystals Al2O3-AlN

Materials and Technical Study

Disorientation Effect in elastic Interaction Energies

Isoenergy Cards

The Mobility of Dislocations under the effect of image force

Conclusions