Analysis of particle induced dislocation structures using three-dimensional dislocation dynamics and strain gradient plasticity

Abstract : Investigations of precipitation hardening are performed in term of analysis of distributions of geometrically necessary dislocations (GND) surrounding particles. The dislocation microstructures are computed from three dimensional discrete dislocation dynamics (DDD) and strain gradient plasticity (SGP) models. DDD simulations of spherical particle embedded in a single crystal matrix undergoing single slip provide the GND structures and the associated work-hardening. A 3D periodic arrangement of particles with cubic symmetry is considered. It is found that a network of slip and kink deformation bands develops, which is strongly dependent on the crystal lattice orientation of the matrix with respect to the particle array. For some relative orientations, the strain hardening is increased by the distributions of GND which act as additional barrier against slip. Some of these features are also captured with the SGP model in contrast to conventional continuum crystal plasticity.