Neutron irradiation effects on the structural, magnetic and mechanical properties of amorphous and nanocrystalline Fe73.5Cu1Nb3Si13.5B9

The response of the structural, magnetic and mechanical properties of amorphous and nanocrystalline Fe_73.5Cu₁Nb₃ Si_13.5B₉ to radiation damage is investigated by means of Mossbauer spectroscopy, hysteresis loop measurements and by bending tests. The irradiation of the nanocrystalline as well as differently thermally treated amorphous samples is performed in the in-core reactor position. Mossbauer experiments reveal that neutron irradiation leads to partial re-amorphization in the investigated nanocrystalline alloys. For all samples it is found that the deterioration of the soft magnetic properties occurs predominantly in the higher fluence range (10¹⁸-10¹⁹ n_th.cm^-2). However, this deterioration is less significant in the nanocrystalline samples. The results of the bending tests show that all samples thermally embrittled below the crystallization temperature (still amorphous) can regain the complete ductility after neutron irradiation. On the other hand, the level of embrittlement of the nanocrystalline samples remained the same even after irradiation to the fluence of 1×10¹⁹ n_th .cm^-2