Microstructural Characterization of Materials for Nuclear Applications Using Small-Angle Neutron Scattering

The results of a small-angle neutron scattering (SANS) investigation of microstructural evolution in martensitic steels, developed for use in future fusion reactors, are presented. Specifically, modified martensitic steel DIN 1.4914 (MANET type), subjected to different thermal treatments, was studied. The separate analysis of the size distribution functions determined from the nuclear and magnetic SANS components provides information on the presence of different inhomogeneities: large carbides and very small (~1-nm) C-Cr elementary aggregates. In the latter case, since they are such small particles at the resolution limit of the technique, the general problem of extracting their SANS signal from the background has been addressed.