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MM: Fachverband Metall- und Materialphysik

MM 22: Topical Session Nanoanalytics using Small-Angle Scattering - Poster

MM 22.1: Poster

Dienstag, 24. März 2009, 14:45–16:30, P4

The ratio of magnetic and nuclear small-angle neutron scattering in neutron-irradiated binary iron alloys — •Frank Bergner and Andreas Ulbricht — Forschungszentrum Dresden-Rossendorf

The effect of neutron irradiation on the formation of defect-solute clusters in binary iron alloys is important for the understanding of the damage mechanisms in structural materials applied in the fields of nuclear technology. These nanoscale features operate as scatterers. The composition of the clusters in terms of solute atoms, iron atoms and vacancies is subject to debate. The A-ratio defined as the ratio of the scattering cross sections perpendicular and parallel to a saturation magnetic field in a sample of a ferromagnetic material provides a link between measurable quantities and cluster composition.

SANS measurements performed for neutron-irradiated binary Fe-Cu, Fe-Ni and Fe-Cr alloys are reported. The analysis is based on the assumption of a two-phase matrix-inclusion topology with inclusions (clusters) fully coherent with the matrix, i.e. clusters consist of atoms of the alloying element, Fe-atoms and/or vacancies confined to lattice sites of a rigid bcc lattice. The values of the A-ratio obtained for Fe-Cu and Fe-Ni can be explained as clusters containing vacancies. The derived vacancy fractions will be specified. For the investigated Fe-9at%Cr alloy the situation is more complex and will be discussed in the paper.