Strain hardening of steels at large strain deformation .3. Model description and physical interpretation

Based on the development of dislocation cell structures during plastic deformation and on the results of computer simulations, a new cell structure-based (CSB) model has been proposed in this part of the work. It is an improvement on the Prinz-Argon model. In comparison with Print and Argon the CSB model enables an analytic correlation between macroscopic stress and strain to be made. In this new model, the two effects of dynamic recovery, dynamic annihilation and reorganization of dislocations, can be taken into account. The entire deformation can be described by this model. According to the model, the remaining strain hardening rate at stage IV is caused by the multiplication of dislocations in the cell interiors. Thus it is not the local flow stress but the local dislocation density change which determines the strain hardening. The Kocks model can be obtained from the CSB model if some simplifications are made.