A unified physically based microstructural representation of face-centred cubic crystalline materials was developed and implemented to investigate the microstructural behaviour of face-centred cubic crystalline aggregates under inelastic deformations. The proposed framework was based upon coupling a multiple-slip crystal plasticity formulation to three distinct dislocation densities, which pertain to statistically stored dislocations, geometrically necessary dislocations and grain boundary dislocations. This interrelated dislocation density formulation was then coupled to a specialized finite element framework to study the evolving heterogeneous microstructure and the localized phenomena that could contribute to failure initiation as a function of inelastic crystalline deformation. The geometrically necessary dislocation densities were used to understand where crystallographic, non-crystallographic and cellular microstructures formed and the nature of their dislocation composition. The statistically stored dislocation densities were formulated to represent dislocation cell microstructures to obtain predictions related to the inhomogeneous distribution of statistically stored dislocations. The effects of the lattice misorientations at the grain boundaries were included by accounting for the densities of the misfit dislocations at the grain boundaries that accommodate these misorientations. By directly accounting for the misfit dislocations, the strength of the boundary regions could be more accurately represented to account for phenomena associated with the effects of the grain boundary strength on intergranular deformation heterogeneities, stress localization and the nucleation of failure surfaces at critical regions, such as triple junctions.

Statistically Stored, Geometrically Necessary and Grain Boundary Dislocation Densities - Microstructural Representation and Modelling. O.Rezvanian, M.A.Zikry, A.M.Rajendran: Proceedings of the Royal Society A, 2007, 463[2087], 2833-53