A model was proposed for the low temperature tensile response of Cu polycrystals with grain sizes in the range of 2 to 50μm. The initial work hardening behaviour was strongly grain size dependent and was considered to arise from a combination of kinematic and isotropic hardening due to dislocation–grain boundary interactions. At larger strains, the influence of grain size on work hardening disappeared owing to processes associated with dynamic recovery at boundaries.
A Model for the Grain Size Dependent Work Hardening of Copper. C.W.Sinclair, W.J.Poole, Y.Bréchet: Scripta Materialia, 2006, 55, 739-42