Small-Angle Neutron Scattering of Precipitates in Ni-Rich Ni-Ti Alloys. II. Methods for Analyzing Anisotropic Scattering Data

Methods for analyzing small-angle neutron scattering data for single crystals with anisometric precipitates and anisotropic arrangement are described. A method for projecting the measured scattering intensity in a (110) plane and obtaining the anisotropic correlation function is described. The method uses an indirect Fourier transformation with Hermitian functions as the basis. The correlation function gives model-independent information on the precipitate form and arrangement. A modified paracrystal cluster model is also introduced and size polydispersity is included in a local monodisperse approximation. The size distribution is obtained by least-squares fitting. The correlation function and the cluster model give consistent results for the morphology of precipitates in Ni-rich Ni-Ti single crystals.