The complex thermal history, high cooling rates and large temperature gradients during the process of laser powder bed fusion (L-PBF) can induce a complex dislocation motion, high dislocation density and unique dislocation structures in the material. The origin of these dislocation structures, their stability during mechanical loading and their effect on crack nucleation and propagation are debated. Experimental analysis of these phenomena is challenging because in-situ electron microscopy techniques cannot be easily used on samples subjected to laser beams during additive manufaturing (AM) processes. However, it is important to understand which factors affect dislocation structures formation in order to optimize the AM process parameters and the structural integrity of the resulting components [1]. To address this problem, a temperature dependent continuum dislocation dynamics (CDD) model is developed that includes several mechanisms, such as dislocation transport, multiplication, annihilation and cross slip. Four state variables are used for each slip system representing the total dislocation density, edge and screw geometrically necessary dislocation densities and dislocation curvature. The CDD model is coupled with a finite strain crystal plasticity solver, which captures the plastic deformation induced by the dislocation motion. A hybrid continuous and discontinuous Galerkin formulation is developed to accurately reproduce the dynamics of highly discontinuous dislocation density fields that are typical of dislocation structures [2]. The coupling between the CDD model and phase field fracture is used to understand the crack nucleation and propagation at the sub-micrometer length scale. A systematic analysis is carried out by investigating the effect of the initial conditions, individual dislocation mechanisms and mechanical load on the dislocation structures formation and their characteristic length scale, which is compared with transmission electron microscopy experiment results. Moreover, the effects of the stress heterogeneity, dislocation density and shape of the cellular dislocation structures on damage are systematically investigated.