Neutron irradiation effects in Fe–Cu–Ni–Mn model alloys studied by measurements of magnetic minor hysteresis loops

Abstract

We have measured magnetic minor hysteresis loops of neutron-irradiated Fe–Cu–Ni–Mn model alloys with variable combinations of Cu and Ni contents. It was revealed that minor-loop coefficients which are in proportion to internal stress decrease after neutron irradiation to a fluence of 0.44 × 10¹⁹ n cm⁻² for all alloys. The decrease of the coefficients strongly depends on both Cu and Ni contents and is enhanced for alloys with high Cu and high Ni contents, in particular. The decrease of the coefficients during neutron irradiation was explained as due to preferential formation of Cu rich and/or Mn-Ni rich precipitates on dislocations which reduces internal stress of dislocations.

Acknowledgements

This research project has been conducted under the research contract with the Japan Nuclear Safety Organization (JNES). We thank Prof. G. R. Odette of UCSB for allowing us to measure neutron irradiated samples, and Dr T. Yamamoto, Dr D. Klingensmith, J. Smith, Dr D. Gragg of UCSB for their assistance in magnetic measurements.