Measurements were made of the magnetic minor hysteresis loops of neutron-irradiated Fe-Cu-Ni-Mn model alloys with various Cu and Ni contents. It was revealed that minor-loop coefficients, which were proportional to internal stress, decreased after neutron irradiation to a fluence of 4.4 x 1018/cm2 for all alloys. The decrease in the coefficients depended strongly upon both the Cu and Ni contents and was enhanced for alloys with high Cu and high Ni contents, in particular. The decrease in the coefficients during neutron irradiation was explained as being due to the preferential formation of Cu-rich and/or Mn-Ni rich precipitates on dislocations, which reduced the internal stress of dislocations.

Neutron Irradiation Effects in Fe-Cu-Ni-Mn Model Alloys Studied by Measurements of Magnetic Minor Hysteresis Loops. S.Kobayashi, H.Kikuchi, S.Takahashi, K.Chiba, Y.Kamada, K.Ara: Philosophical Magazine, 2007, 87[26], 4047-58