Hydrogen-induced intergranular failure of iron

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

    Research output: Contribution to journalArticlepeer-review

    135 Citations (Scopus)

    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
    Pages (from-to)275-282
    Number of pages8
    JournalActa Materialia
    Volume69
    DOIs
    Publication statusPublished - May 2014

    All Science Journal Classification (ASJC) codes

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

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