Effects of neutron-irradiation-induced intergranular phosphorus segregation and hardening on embrittlement in reactor pressure vessel steels

Y. Nishiyama, K. Onizawa, M. Suzuki, J. W. Anderegg, Y. Nagai, T. Toyama, M. Hasegawa, J. Kameda

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51 Citations (Scopus)

Abstract

The effects of intergranular P segregation and hardening on the ductile-to-brittle transition temperature (DBTT) in several neutron-irradiated reactor pressure vessel steels with different bulk contents of P and Cu have been investigated using a scanning Auger microbe, a local electrode atom probe and positron annihilation spectroscopy. Increasing the neutron fluence at 563 K promotes intergranular P segregation, particularly in steels with high levels of P. The content of P (<570 ppm) more significantly affects irradiation-hardening than that of Cu (<0.17 wt.%) due to distinct formation of P-rich precipitates arising from the stabilization of vacancies. Analyzing the correlations between P segregation, hardening, fraction of intergranular fracture and DBTT, it is found neutron irradiation mitigates the embrittling effect of segregated P, and therefore the hardening more strongly affects the DBTT shift than the P segregation, with the exception of highly P-doped steel irradiated to high neutron fluence.

Original languageEnglish
Pages (from-to)4510-4521
Number of pages12
JournalActa Materialia
Volume56
Issue number16
DOIs
Publication statusPublished - 2008 Oct 1

Keywords

  • Grain-boundary segregation
  • Hardening
  • Irradiation embrittlement
  • Precipitate
  • Reactor pressure vessel steels

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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