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 ~16 nm and their proper quantitative analyses. The smaller scattering centres in the ODS alloy exhibit distributions with modal values at ~6–7 and 12–14 nm. The peak at ~6–7 nm appears to be due to the overlapping of more than one type of scattering centres, while the one at ~12–14 nm 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 0.77 × 10²² m⁻³, respectively.

Keywords:

• oxide dispersion strengthening
• small-angle neutron scattering
• maximum entropy method
• positron annihilation spectroscopy
• transmission electron microscopy

Acknowledgements

The Authors are grateful to the laboratory Forschungs-Neutronenquelle Heinz Maier-Lebnitz (FRM II) for making all the facilities available, to the Department of Materials at the University of Oxford for valuable TEM discussions and to the European Commission for the support through the European Fusion Development Agreement.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This investigation was supported by the Spanish Ministry of Science and Innovation [grant number ENE2010-17462]; Comunidad de Madrid through the program ESTRUMAT-CM [grant number S2009/MAT-1585]; European Union under the 7th Framework Program [grant number 312483]; and ESTEEM2 (Integrated Infrastructure Initiative-I3) and the Royal Society International Exchanges Scheme 2011/R1 [grant number IE110136].