Neutron Diffraction and Small-Angle Scattering as Nondestructive Probes of the Microstructure of Materials

Abstract

Thermal neutron scattering is a well established research tool for determining the atomic structure and fundamental excitations of solids and liquids. In addition, wide-angle diffraction has been employed for many years for the study of appropriate technological problems. In recent years, a growing area of interest in this field has been the development of scattering techniques which extend the scale of the structural information obtained to dimensions which are typical of the microstructure of a material as compared to its atomic structure. Such techniques, of which small-angle neutron scattering (SANS) is a prime example, yield information which is complementary with that obtained by electron microscopy or analogous x-ray methods. The neutron techniques afford the added advantage that the measurements may be made on relatively thick specimens or on samples in specialized environments owing to the highly penetrating nature of neutron radiation. The derived information is thus characteristic of the bulk material and can be correlated with bulk measurements carried out, in many cases, on the very same samples. Neutron scattering, therefore, has a natural role to play in the nondestructive investigation of materials properties.