Magnetic investigations on irradiation-induced nanoscale precipitation in reactor pressure vessel steels: A first-order reversal curve study

JOURNAL OF NUCLEAR MATERIALS

卷:552

Article

Kobayashi, Satoru¹  Murakami, Hiroaki¹  Yamamoto, Takuya²  Odette, G. Robert²  Horvath, Akos³  Feoktystov, Artem⁴  Almasy, Laszlo³ 

[1] Iwate Univ, Fac Sci & Engn, Ueda 4-3-5, Morioka, Nagano 0208551, Japan

[2] Univ Calif Santa Barbara, Dept Mech & Environm Engn, Santa Barbara, CA 93106 USA

[3] Ctr Energy Res, POB 49, H-1525 Budapest 114, Hungary

[4] Forschungszentrum Julich, Julich Ctr Neutron Sci JCNS, Heinz Maier Leibnitz Zentrum MLZ, D-85748 Garching, Germany

关键词: Neutron irradiation;    Magnetic hysteresis;    SANS;    First-order-reversal curves;    Pressure vessel;   

DOI  :  10.1016/j.jnucmat.2021.152973

来源: Elsevier

【 摘 要 】

We have investigated magnetic properties for reactor pressure vessel model alloys with variable Cu contents, subjected to neutron irradiation up to a fluence of 9 x 10 19 n cm-2 . Unlike a monotonic increase of microhardness with neutron fluence, the major-loop coercivity decreases at a higher fluence and the decrease becomes larger for the alloy containing a higher amount of Cu. The measurements of first-order reversal curves (FORCs) for the high-Cu alloy show that the position of the FORC distribution peak shifts toward a lower coercivity just after neutron irradiation, followed by a slight increase, associated with the broadening along both the coercivity and interaction field axes. The results can be explained by the enhancement of magnetic inhomogeneity in a matrix due to Cu precipitation and an increasing magnetostatic interaction between local magnetic regions with different coercivity. The magnetic method using FORCs can be a possible technique which provides in-depth information on microstructural changes due to neutron irradiation, which is not obtained by measurements of a conventional major hysteresis loop. (c) 2021 Elsevier B.V. All rights reserved.

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