PREDICTING GRAIN REFINEMENT BY COLD SEVERE PLASTIC DEFORMATION PROCESSES IN ALLOYS BY USING THE METHOD OF VOLUME AVERAGED DISLOCATION GENERATION

Abstract

he grain refinement during severe plastic deformation processes is predicted using volume averaged amount of dislocations generated. The model incorporates a new expansion of a model for hardening in the parabolic hardening regime, in which the work hardening depends on the effective dislocation free path related to the presence of non shearable particles and solute-solute nearest neighbour interactions. These two mechanisms give rise to dislocation multiplication in the form of generation of geometrically necessary dislocations and dislocations induced by local bond energies. The model predicts the volume averaged amount of dislocations generated and considers that they distribute to create cell walls and move to existing cell walls/grain boundaries where they increase in the grain boundary misorientation.