A new dislocation-mechanics based crystallographic theory was developed in order to model the mechanical behavior of single-phase face-centered cubic polycrystalline aggregates. In this theory, the dislocations were discretized into edge and screw components, with intrinsically different relative mobilities, and were subjected to differing dynamic recovery processes. The theory was used in a finite-strain and rate-dependent constitutive framework, and was applied to a thin polycrystalline Cu specimen in order to investigate the effect of intragranular lattice misorientations upon the deformation behavior. The misorientations represented low-angle grain boundaries, which were known to play an important role in the evolution of polycrystals under monotonic and cyclic deformation. This revealed that the presence of these misorientations strengthened the material response by suppressing and re-distributing the localization of slip within the grains, as well as inhibiting the formation of sub-grains. The model also predicted the presence of a higher proportion of edge dislocations in the vicinity of localized slip regions.

Discrete Dislocation Density Modelling of Single Phase FCC Polycrystal Aggregates. K.S.Cheong, E.P.Busso: Acta Materialia, 2004, 52[19], 5665-75