During plastic deformation, a metallic structure is deformed inhomogeneously near hard inclusions. Hence both the materials strengthening and recovery and thus softening depends on the local position. There are thus high gradients of point defects, such as vacancies and interstitials, of the dislocation density and hence of the strain energy. Those gradients govern the diffusional flow, whose pile-up influences the climbing of edge dislocations, i.e. recovery and materials softening, respectively.