The irreversibility of dislocation-wall formation in persistent slip bands

Abstract By cyclic deformation of copper single crystals with an amplitude of resolved plastic shear strain pl≍ M ≍ 1·2 × 10 −4 at 300 K, a saturated hard matrix structure was established. Then a certain volume fraction of the matrix was transformed into persistent slip bands (PSBs) by increasing pl. After this step the cyclic deformation was continued with an amplitude pl ≤ M up to cumulative plastic strains of more than 40 in order to test whether it is possible to retransform the characteristic ladder-like dislocation arrangement of PSBs into a matrix-like structure. Transmission electron microscopy revealed that such a retransformation did not occur.