A dislocation based analysis of continuum mechanical and microscopic local stresses during cyclic deformation of copper

A relationship between continuum mechanical internal stress variables, kinetic back stress, isotropic drag stress, and microscopic local stresses in the dislocation cell interior and cell walls, is developed based upon Mughrabi's composite model of deformation of heterogeneous microstructure during cyclic deformation in cell forming metals. The experimental data on the evolution of kinematic back stress and isotropic drag stress during cyclic deformation of Cu along with TEM measurements of cell diameter and cell width are utilized to determine the evolution of mobile and immobile dislocation densities in the cell interior and cell walls, respectively, as a function of the number of cycles. The range of values obtained is in agreement with the available experimental data.