Characteristics of hydrogen-assisted intergranular fatigue crack growth in interstitial-free steel: role of plastic strain localization

Motomichi Koyama, Yosuke Onishi, Hiroshi Noguchi

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The behavior of intergranular fatigue crack growth in an interstitial-free (IF) steel in a hydrogen environment was investigated at different frequencies. Focusing on the plastic strain localization, we observed details of the striation-like feature on the intergranular fracture surface, slip behavior around microvoids, and crystallographic orientation gradient underneath the fracture surface. It was determined that the intergranular fatigue crack growth mechanism in the IF steel is microvoid formation at the crack tip and subsequent coalescence with the crack. Moreover, it was found that the grain boundaries, acting as propagation paths, suffer from pre-damage arising from plastic strain localization near the grain boundaries even before the main crack propagates to a certain location. Therefore, fatigue cracks in a hydrogen environment easily propagate to the grain boundaries. The frequency dependence of fatigue crack growth in the hydrogen environment is significantly smaller than that in a low carbon steel, probably because of the frequency dependence of the pre-damage evolution behavior.

Original languageEnglish
Pages (from-to)123-130
Number of pages8
JournalInternational Journal of Fracture
Volume206
Issue number1
DOIs
Publication statusPublished - Jul 1 2017

All Science Journal Classification (ASJC) codes

  • Computational Mechanics
  • Modelling and Simulation
  • Mechanics of Materials

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