LONG-RANGE INTERNAL-STRESSES IN CELL AND SUBGRAIN STRUCTURES OF COPPER DURING DEFORMATION AT CONSTANT STRESS

Long-range internal stresses in dislocation cell and subgrain structur es were investigated experimentally. The transition oi the dislocation structure from cells to subgrains was achieved by deforming copper po lycrystals in compression creep tests at constant stress normalized by the shear modulus in the temperature range from 298 K to 633 K. The l ong-range internal stresses were investigated by two methods. The firs t one was the evaluation of characteristically asymmetric X-ray line p rofiles. The internal stresses are the result of the analysis oi the X -ray line profiles. The second one was the measurement of local lattic e parameters by convergent beam electron diffraction. The internal str esses can be determined from the changes in the local lattice paramete rs. The results obtained from both methods show that long-range intern al stresses of the same type exist in the cell as well as in the subgr ain structures. Copyright (C) 1996 Acta Metallurgica Inc.