Development a dislocation density based model considering the effect of stacking fault energy: Severe plastic deformation

Considering the effect of an intrinsic material parameter, stacking fault energy (SFE), a model based on dislocation density is developed to investigate the evolutions of dislocation density, cell size and flow stress during severe plastic deformation of aluminum and nickel. In fact a model is presented considering the work hardening and different annihilation mechanisms for dislocation densities in cell interiors and cell walls. Annihilation terms are developed on the basis of SFE through the model. The calculations show that the total dislocation density, dislocation density in cell interiors, dislocation density in cell walls and flow stress are decreased with increasing SFE. To verify the model results, they are compared with the experimental data and a good agreement is observed.