Small-angle neutron scattering was applied to investigate Fe-based model alloys with intentionally varied Cu levels. The aims were to provide size distributions of scatterers and to interpret deviations of the measured ratio of magnetic and nuclear scattering cross-sections from the ratios calculated for pure vacancy clusters and pure Cu clusters. In the case of the low-Cu alloy, the small-angle neutron scattering results indicated that the average scatterer was an Fe-Cu-vacancy cluster of about 1nm in radius. In the case of Cu-enriched alloy, the small-angle neutron scattering results were consistent with Cu-rich clusters of about 1.5nm in radius, containing 15% vacancies per body-centred cubic lattice site.

Nature of Defect Clusters in Neutron-Irradiated Iron-Based Alloys Deduced from Small-Angle Neutron Scattering. F.Bergner, A.Ulbricht, A.Gokhman, D.Erak: Journal of Nuclear Materials, 2008, 373[1-3], 199-205