The microstructure of neutron-irradiated Fe-Cr alloys: A small-angle neutron scattering study

The effect of Cr on the microstructures of neutron-irradiated Fe-Cr alloys is not yet known in all details including types, sizes, concentrations and compositions of irradiation-induced features on the nanoscale. Such details are needed in order to develop and validate models devoted to the long-term evolution of microstructures. Among other techniques, small-angle neutron scattering (SANS) can contribute to this task. Results obtained for a set of Fe-Cr alloys of Cr levels of 2.5, 5, 9 and 12.5 at%, irradiated at 300°C up to neutron exposures of 0.6 and 1.5 dpa are reported. We have found that the incoherent magnetic scattering of the unirradiated alloys exhibits a systematic variation with the Cr content and that there is an irradiation-induced increase of the coherent magnetic scattering for each of the irradiated conditions. The effect of Cr on size and type of irradiation-induced scatterers is discussed.