Abstract
Typical dislocation configurations appearing after cyclic deformation of nickel crystals oriented for single slip are the ladder-like arrangements in persistent slip bands (PSBs) and the bundle structure in the matrix. Long-range internal stresses are expected to arise in the PSBs. The change of these stresses within the deformation cycle is investigated by an analysis of asymmetric X-ray line profiles. For crystals with a pure matrix structure or with a low volume fraction of PSBs, no significant long-range stresses occur. In dislocation structures with a PSB volume fraction above 20%, long-range stresses could be resolved changing their sign within each half-cycle. The saturation of the internal stresses within each half-cycle indicates macroyielding which may be interpreted as plastic yielding of the PSB walls at a local yield stress of about 120 MPa.
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