Small-Angle Neutron Scattering from Anisotropic Single-Crystalline Materials

`Isotropic' small-angle scattering (SAS), i.e. without azimuthal dependence around the primary beam, occurs only for specific configurations of the scattering objects if single-crystalline material is studied. For decomposing Ni-based alloy single crystals, SAS signals are generally highly anisotropic. From analysis of two-dimensional SAS patterns, important information on the evolution of the morphology and on the three-dimensional spatial arrangement of the precipitates from the early stages of decomposition can be extracted. The real-space information obtained from transmission electron microscopy is an excellent complement to the reciprocal-space information extracted from SAS data. The complementary use of these two techniques offers a valuable approach to the study of precipitation phenomena.