MICROMECHANICAL ANALYSIS OF THE DISLOCATI ON CELLS FORMATION AND CONSEQUENCES IN STEEL BEHAVIOR

A micromechanical model is proposed describing the formation and devel opment of dislocation cells in the grains of a BCC polycrystal. The gr ain is considered as a two-phase material in which the boundaries of t he << phase >> constitute mobile barriers. Analysis of the energy diss ipation makes the thermodynamic forces on the internal variables appea r. Application indicates a large heterogeneization effect, especially for third order internal stresses, in agreement with the Mughrabi meas urements.