A continuum dislocation-based model that described the size-dependent plasticity at the microscale, by considering evolving fields of curved dislocations, was enhanced by a refined treatment of short-range interactions between dislocations. In addition to the Taylor-type stress, a back-stress that took account of the relative orientation of the interacting dislocations was implemented. Its influence upon the physical content of the model, as well as upon its numerical character, were investigated and the effect of the Taylor relationship and back-stress were compared. It was deduced that these two stresses could be considered as being valid extremes for the description of the short-range interactions for high and low dislocation densities, respectively. The influence of the back-stress upon a previous interpretation of the so-called source-shortening effect, using the present model, was described.

Refined Short-Range Interactions in the Continuum Dislocation-Based Model of Plasticity at the Microscale. C.Schwarz, R.Sedláček, E.Werner: Acta Materialia, 2008, 56[3], 341-50