Hydrogen-induced intergranular failure of iron

Shuai Wang, May L. Martin, Petros Sofronis, Somei Ohnuki, Naoyuki Hashimoto, Ian M. Robertson

Research output: Contribution to journalArticle

Abstract

The hydrogen embrittlement of a commercial-grade pure iron was examined by using repeated stress-relaxation tests under simultaneous cathodic hydrogen charging. The hydrogen-charged iron, containing an estimated 25.8 appm H, fractured after repeated transients, with a total strain of ∼5%. The fracture mode was intergranular. Thermal activation measurements show a decrease in activation volume and free energy, which is consistent with hydrogen enhancing the dislocation velocity. The microstructure beneath the intergranular facets displays a dislocation cell structure more complex than expected for intergranular fracture and this strain-to-failure. It is proposed that hydrogen accelerates the evolution of the dislocation microstructure through the hydrogen-enhanced plasticity mechanism and this work-hardening of the matrix along with the attendant hydrogen concentration at the grain boundaries are crucial steps in causing the observed hydrogen-induced intergranular failure.

Original languageEnglish (US)
Pages (from-to)275-282
Number of pages8
JournalActa Materialia
Volume69
DOIs
StatePublished - May 2014

Keywords

  • Hydrogen embrittlement
  • Iron
  • Mechanical properties
  • Transmission electron microscopy

ASJC Scopus subject areas

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

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  • Cite this

    Wang, S., Martin, M. L., Sofronis, P., Ohnuki, S., Hashimoto, N., & Robertson, I. M. (2014). Hydrogen-induced intergranular failure of iron. Acta Materialia, 69, 275-282. https://doi.org/10.1016/j.actamat.2014.01.060