Small-angle neutron scattering study of the nano-sized features in an oxide dispersion-strengthened Fe12Cr alloy

Abstract

Small-angle neutron scattering experiments, along with positron lifetime measurements and transmission electron microscopy observations, were performed on samples of an oxide dispersion-strengthened (ODS) Fe12Cr alloy and its non-ODS counterpart in order to characterize their nano-sized features. The nuclear and magnetic scattering data were analysed using the maximum entropy approach for obtaining the size distribution of the scattering centres in these materials. The positron annihilation results and the TEM information have made possible an interpretation of the volume distribution of the scattering centres having sizes below ~16nm and their proper quantitative analyses. The smaller scattering centres in the ODS alloy exhibit distributions with modal values at ~6-7 and 12-14nm. The peak at ~6-7nm appears to be due to the overlapping of more than one type of scattering centres, while the one at ~12-14nm can be exclusively attributed to the Y-rich centres. The quantitative analysis of the magnetic scattering data yields a volume fraction and number density of the Y-rich particles estimated in 0.70 +/- 0.03% and 0.77x10(22)m(-3), respectively.