Radiation Damage of Fe-based Nanocrystalline Materials

Nanocrystalline (Fe1−xNix)81Nb7B12 (x = 0, 0.25, 0.5, 0.75) and Vitroperm alloys were studied by Mossbauer spectroscopy after neutron irradiation at uences of 10 n/cm and 10 n/cm. From structure analyses, we have identi ed ferromagnetic bcc-FeNi in nanocrystalline state and partly paramagnetic (Fe-Ni)23B6 phase. Neutron irradiation had an in uence on the magnetic microstructure, which is manifested in the change of the Mossbauer parameters, such as the direction of net magnetic moment, the intensity of internal magnetic eld and the volumetric fraction. The results indicate that the changes of the microscopic magnetic parameters, induced by neutron irradiation, depend on iron and nickel content. Signi cant radiation damage started at neutron uence of 10 n/cm.