Effects of releasing the hydrostatic pressure on the nanostructure after severe plastic deformation of Cu

Changes in the microstructure related to the release of hydrostatic pressure after high-pressure torsion deformation of Cu were studied by freezing the sample before releasing the pressure. Investigations were performed by X-ray line profile analysis using synchrotron radiation. The size of the coherently scattering domains is not strongly affected whereas the dislocation density decreases drastically and the arrangement of the dislocations within the subgrain structure changes to a less stress-intensive one upon pressure release.