A note on dislocation-cell structures in commercial copper

The variation of dislocation-cell size with strain, expressed as a reduction in the area of broken specimens, was studied in copper specimens of commercial purity. Furthermore, the relationship between cell size and stress was also investigated at high strains and was compared with earlier work which had been performed at much lower stresses and strains. It was found that above a certain critical strain the dislocation cells did not decrease further in size and eventually transformed into subgrains before fracture occurred. Also, there is an indication that the saturation of dislocation density occurs simultaneously with the formation of cells of minimum size.