Experimental Validation of Edge Dislocation Theory Model

Experimental measurement of deformation fields around the edge dislocation core is a very difficult research task over the years.It has led to the coexistence of several dislocation models.To validate the applicability of edge dislocation model,an edge dislocation in polycrystalline gold was observed directly by transmission electron microscope and high-resolution microscopy image of the edge dislocations was obtained successfully.Displacement fields and strain fields around the edge dislocation were mapped by geometric phase analysis method.Displacement and strain measurement results were compared with the isotropic elastic theory dislocation model,the Peierls-Nabarro dislocation model and the Foreman(a=4)dislocation model,respectively.Comparison results show that three theory models are all available for describing edge dislocation deformation field in the areas far from the dislocation core.But strain measurement shows a good agreement with Peierls-Nabarro dislocation model in the vicinity of dislocation core.