The influence of neutron irradiation on the soft magnetic and mechanical properties of amorphous and nanocrystalline Fe73.5Cu 1Nb3Si13.5B9 alloys

Abstract

The changes in the magnetic and mechanical properties of Fe 73.5Cu1Nb3Si13.5B9 alloys after various annealing and neutron irradiation treatments were studied by hysteresis loop measurements and by bending tests. It was shown that annealing of the amorphous alloy slightly above its crystallization temperature leads to the formation of an ultrafine grain structure of α-Fe(Si) with an average grain diameter of about 11 nm embedded in an amorphous matrix. The resulting nanocrystalline samples exhibit very good soft magnetic properties but their mechanical properties are deteriorated. In order to evaluate and compare the resistance of amorphous and nanocrystalline samples to radiation damage and the correlated microstructural changes, specimens of the alloys investigated were irradiated in the in-core reactor position. Deterioration of the soft magnetic properties after neutron irradiation was found to be less significant in the case of nanocrystalline samples. The state of embrittlement of the samples investigated is not influenced by neutron irradiation up to a fluence of 10 19 nth cm-2. Post-irradiation thermal treatments revealed that irradiation-induced defect structures may recover after annealing below the crystallization temperature.