Discrete dislocation modeling in three-dimensional confined volumes

Plastic deformation of micron-sized specimens or smaller cannot be described by continuum plasticity, as the discrete nature of the dislocations can no longer be ignored. This paper presents a three-dimensional dislocation dynamics plasticity method developed for the study of plasticity of such small specimens. The approach includes two components: (i) plasticity is described by the dynamics of individual, discretized three-dimensional dislocation loops; (ii) a finite element model supplies ‘image fields’ that incorporate traction or displacement boundary conditions on the specimen. ular dislocation loop is used to validate the chosen discretization of the dislocation. The critical stress for activating a Frank–Read source confirms the used line-tension description. A tensile test of a free-standing thin film illustrates the incorporation of the boundary conditions into the model. Particular attention is given to the treatment of dislocation loops that have glided partly out of the body, leaving a step at the surface.