Dislocation clustering and long-range internal stresses in monotonically and cyclically deformed metal crystals

Abstract

Dislocation wall and cell structures in deformed metal crystals are reviewed briefly, emphasizing the heterogeneity of the dislocation distribution. The evolution of the dislocation substructure is discussed in terms of work hardening and dynamic recovery. The main part of the paper deals with the so-called composite model in which the heterogeneous dislocation distribution is considered as a composite consisting of bonded hard and soft components corresponding to cell walls and cell interiors, respectively. Long-range internal stresses whose magnitude is consistent with experiment are an integral part of the composite model. They arise as a necessary consequence of the compatibility requirements during deformation. The composite model leads to a new understanding of the macroscopic flow stress and to a good description of reverse loading including the Bauschinger effect in the case of single crystals.