Determination of interfacial residual stress field in an Al–Al2O3 composite using convergent-beam electron diffraction technique

The interface residual stress field in a particulate reinforced composite Al–Al2O3 was studied by means of large-angle convergent-beam electron diffraction (LACBED) technique. When the illuminated area contains an Al2O3 particle, the diffraction lines near the ellipsoid-like particle become split. The splitting of diffraction lines maps the spatial variation of the residual strain around the particle. A model for computing the displacement field around a particle in TEM foil was constructed on the basis of Eshelbyʹs equivalent inclusion method. Taking the equivalent eigenstrain as one of the adjustable parameters, the eigenstrain is determined by fitting the simulated LACBED patterns to the experimental patterns. The factors influencing the LACBED patterns and the accuracy in determination of the strain field with this method are discussed.