Influence Of Strain Rate On Grain Refinement By Plastic Deforming

Severe plastic deformation (SPD) processing, especially Equal-Channel Angular Pressing (ECAP), has attracted increasing interest recently with its prominent advantages, such as cleanness and densification, in obtaining materials of ultrafine grains/nanocrystallines.Equal-Channel Angular Pressing of pure Al and pure Cu was successfully carried out at room temperature with route Bc at different strain rates. The results show that the finer grains both for Al and for Cu obtained at the higher strain rate.In this study, dislocation cells by conventional compression with strain of 6% as well as saturated grains by ECA-pressing were obtained at the same equivalent strain rate. It was found that the sizes of these two kinds of structures show a proportional relationship. Dislocation slipping is the principal mechanism for grain refinement in aluminum because of its high...