Disorder-induced melting in nickel: Implication to intergranular sulfur embrittlement

J. K. Heuer, P. R. Okamoto, N. Q. Lam, J. F. Stubbins

Research output: Contribution to journalArticlepeer-review


Why and how sulfur segregation leads to intergranular embrittlement of nickel has been investigated by a combination of Auger electron spectroscopy, slow-strain-rate tensile tests, ion-implantation, and Rutherford backscattering spectrometry studies. Grain-boundary sulfur concentrations in dilute Ni-S alloys were systematically varied by time-controlled annealing of specimens at 625 °C. The critical sulfur concentration for 50% intergranular fracture of 15.5±3.4 at.% S was found to be, within experimental error, equal to the critical implant concentration of 14.2±3.3 at.% S required to induce 50% amorphization of single-crystal nickel during S+ implantation at liquid nitrogen temperature. This suggests that segregation-induced intergranular embrittlement, like implantation-induced amorphization, may be a disorder-induced melting process, albeit one occurring locally at grain boundaries. In addition, a kinetic model for segregation-induced embrittlement based on Poisson statistics is introduced, and the synergistic effects of hydrogen-sulfur co-segregation on embrittlement are discussed.

Original languageEnglish (US)
Pages (from-to)129-141
Number of pages13
JournalJournal of Nuclear Materials
Issue number2-3
StatePublished - Mar 2002

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Materials Science(all)
  • Nuclear Energy and Engineering

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