By using scattering theory, the dislocation content of coarse-grained -brass samples was investigated by means of line-shape analysis after compression at room temperature and 300C. The diffraction peaks were measured by using a double-crystal spectrometer, 2 different conventional X-ray powder diffractometers, and a high-resolution triple-axis neutron spectrometer. It was noted that, due to inhomogeneous deformation of the polycrystals, the results which were determined by means of X-ray diffraction were only valid for the observed crystallite whereas the neutron data provided a volume-weighted average dislocation content. These values corresponded to the degree of deformation and to the applied stress, respectively. No dependence of the line-shape upon the amount of deformation or upon the temperature was detected; thus suggesting that the dislocation pile-ups did not contain a large number of super-dislocations. This was attributed to cross-slip or twinning. It was concluded that X-ray profile measurements which were made by using a common powder diffractometer were as reliable as those made using high-resolution optics; provided that the dislocation content of the samples was relatively large. When applied to fine-grained materials, it demonstrated the advantage of averaging the defect density.

D.Breuer, P.Klimanek: Materials Science Forum, 1996, 228-231, 67-72