- The effect of strain on the microstructure and detailed internal structure of dislocation boundaries in pure polycrystalline fcc metals (aluminum, copper, nickel and gold) was systematically studied and compared as a function of strain following compression at room temperature. At low strains all metals form a cellular structure. The dislocations in the cell walls tend to rearrange themselves from tangles to ordered arrays of parallel dislocations as the strain is increased. However the rearrangement does not correlate well with the stacking fault energy. A good correlation is found with the cross-slip activation energy.