Characteristics of Barkhausen noise and permeability on neutron irradiated pure Fe and Fe-Cu alloy

Issue title: Selected Papers from the 15th International Symposium on Applied Electromagnetics and Mechanics (ISEM 2011)

Article type: Research Article

Authors: Kikuchi, Hiroaki^{a; *} | Kamada, Yasuhiro^a | Kobayashi, Satoru^a | Echigoya, Jyunichi^a | Watanabe, Hideo^b

Affiliations: [a] Faculty of Engineering, Iwate University, Iwate, Japan | [b] Research Institute for Applied Mechanics, Kyushu University, Fukuoka, Japan

Correspondence: [*] Corresponding author: Hiroaki Kikuchi, Faculty of Engineering, Iwate University, Morioka, Iwate 020-8551, Japan. Tel.: +81 19 621 6890; Fax: +81 19 621 6890; E-mail: hkiku@iwate-u.ac.jp

Abstract: This paper describes the characteristics of magnetic Barkhausen noise (MBN) and permeability on neutron irradiated Fe and Fe-Cu alloys. The plates made of pure Fe and Fe-1 wt.% Cu alloys were prepared with and without cold-rolling. Those plates were irradiated by neutron with a total fluence of 1 × 10^{24} n/m^{2}. Then MBN properties and impedance were measured using magnetic-yokes, a MBN sensor and a pick-up coil. The MBN rms voltage decreases with neutron irradiation, and the impedance increases after irradiation for cold-rolled specimen. On the other hand, the MBN properties and the impedance at lower frequency have no significant changes after irradiation for undeformed specimen. Contrary, the impedance at higher frequency for undeformed Fe-Cu alloy decreases after irradiation. The relations between those magnetic properties and the microstructure of irradiated materials were also discussed. Those results show the potential of nondestructive evaluation for neutron irradiation embrittlement in reactor pressure vessels.

Keywords: Barkhausen noise (MBN), permeability, impedance, nondestructive evaluation (NDE), neutron irradiation, dislocation, Cu precipitation

DOI: 10.3233/JAE-2012-1518

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 609-614, 2012