The X-ray Bragg profile-analysis dislocation densities, arrangements and long-range internal stresses in cold-worked polycrystalline samples were determined by using synchrotron radiation. Room-temperature torsionally deformed samples having different degrees of deformation were investigated by making scanning measurements across single grains, using a focal spot of less than 50μm, in order to obtain information on the characteristics of the deformation-induced sub-structure. At small deformations which included stage III, the dislocation densities and internal stresses were uniform within single grains. At higher deformations, in stages IV and V, the dislocation density and internal stress exhibited correlated fluctuations. The fluctuations in stage IV were identified as being polarized tilt walls which were formed from polarized dipole walls.

Microscale Spatial Distribution of Dislocations and Long-Range Internal Stresses in Cold-Worked BCC Fe. E.Schafler, M.Zehetbauer, T.Ungar, S.Bernstorff, H.Amenitsch: Key Engineering Materials, 2000, 177-180, 159-64