In-situ observation of small-angle X-ray scattering by dislocations

Ultra-small-angle X-ray scattering by dislocations in single-crystal alumin um has been observed in situ as a function of plastic deformation. The scat tering is strongly dependent upon sample orientation, with single dislocati ons, dislocation dipoles, and the dislocation distribution within walls eac h exhibiting distinct scattering profiles. Among the microstructural featur es that have been observed are: the correlations between the ordered fracti on of dislocations, the presence of dislocation dipoles, the increasing dis location content with increasing strain, and the decreasing width of the in terface between dislocation walls and the surrounding nearly-dislocation-fr ee material with increasing deformation.