Early stage SCC initiation analysis of fcc Fe-Cr-Ni ternary alloy at 288 °C: A quantum chemical molecular dynamics approach

Nishith Kumar Das, Ken Suzuki, Kazuhiro Ogawa, Tetsuo Shoji

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

The initiation of stress corrosion cracking in fcc Fe-Cr-Ni ternary alloys was studied by means of quantum chemical molecular dynamics at 288 °C. This study showed that the iron and chromium atoms segregate faster than nickel atoms at the surfaces. The atomic model showed that nickel enrichment occurred at the inner oxide layer. The binding energy helps reduce the mobility of the nickel atoms. The surface morphology showed that Fe, Cr, and O accumulate on the very top surface while Fe, Cr, Ni, and O bonding takes place beneath this revealing the formation of an outer and inner oxide film. The diffusion of oxygen and hydrogen into the surface increases when it is under strain. The deeply diffused hydrogen becomes negatively charged by taking electron from metal atoms. Consequently, the process weakens the metallic bonds following with the result that oxygen can diffuse easily into the surface. It seems that hydrogen effectively functions as an oxygen carrier. This kind of reaction process can take place in the molecular domain of a crack tip and thus play a vital role in initiating the SCC process.

Original languageEnglish
Pages (from-to)908-913
Number of pages6
JournalCorrosion Science
Volume51
Issue number4
DOIs
Publication statusPublished - 2009 Apr 1

Keywords

  • A. Austenitic stainless steel
  • B. Modelling studies
  • C. Effects of strain
  • C. Stress corrosion

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)

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