Non-local plasticity at microscale: A dislocation-based and a Cosserat model

An interpretation of intrinsic length seals in materials containing plastic ally soft and hard phases is proposed, based on the idea that dislocations gliding in the soft phase have to bow between thr hard phase. Accordingly, the self-energy (line-tension) of the bowing dislocations is introduced int o the continuum mechanics description of the plastic deformation. A direct relation between a simple dislocation-based and a Cosserat model is establi shed, allowing for identification of the Cosserat intrinsic length, rotatio n and curvature. Attention is also paid to the question whether the geometr ically necessary dislocations contribute primarily to isotropic or to kinem atic hardening.