Neutron irradiation effects on magnetic minor hysteresis loops in nuclear reactor pressure vessel steels |
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Authors: | S Kobayashi H Kikuchi S Takahashi Y Kamada K Ara T Yamamoto |
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Institution: | 1. Faculty of Engineering, NDE and Science Research Center , Iwate University , Morioka, 020-8551, Japan koba@iwate-u.ac.jp;3. Faculty of Engineering, NDE and Science Research Center , Iwate University , Morioka, 020-8551, Japan;4. Department of Mechanical Engineering , University of California Santa Barbara , Santa Barbara, CA, 93106-5080, USA |
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Abstract: | Magnetic minor hysteresis loops have been measured on A533B-type nuclear reactor pressure vessel steels with various combinations of Cu and Ni contents after neutron irradiation to a fluence up to 3.32 × 1019 n cm?2. A strong compositional dependence of minor-loop properties, which are indicators of internal stress, was found. The properties of high-Cu and high-Ni steel show a large increase in the low fluence regime below 0.4 × 1019 n cm?2, followed by a slow decrease, while those for low-Cu or low-Ni steel show a sudden decrease. The changes are roughly in linear proportion to the yield strength changes. The results were explained from the viewpoint of the formation and growth of Cu-rich precipitates and/or fine scale defects in the matrix and along pre-existing dislocations. |
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Keywords: | magnetic hysteresis irradiation effects magnetic properties nanoscale precipitates neutron irradiation nuclear materials |
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