Three-dimensional imaging of hydrogen blister in iron with neutron tomography

Axel Griesche, Eitan Dabah, Thomas Kannengiesser, Nikolay Kardjilov, André Hilger, Ingo Manke

Research output: Contribution to journalArticlepeer-review

116 Scopus citations

Abstract

We investigated hydrogen embrittlement and blistering in electrochemically hydrogen-charged technical iron samples at room temperature. Hydrogen-stimulated cracks and blisters and the corresponding hydrogen distributions were observed by neutron tomography. Cold neutrons were provided by the research reactor BER II to picture the sample with a spatial resolution in the reconstructed three-dimensional model of ∼25 μm. We made the unique observation that cracks were filled with molecular hydrogen and that cracks were surrounded by a 50 μm wide zone with a high hydrogen concentration. The zone contains up to ten times more hydrogen than the bulk material. The hydrogen enriched zone can be ascribed to a region of increased local defect density. Hydrogen also accumulated at the sample surface having the highest concentration at blistered areas. The surfaces of the brittle fractured cracks showed micropores visualized by scanning electron microscopy. The micropores were located at grain boundaries and were surrounded by stress fields detected by electron backscattered diffraction. The cracks clearly originated from the micropores.

Original languageEnglish
Pages (from-to)14-22
Number of pages9
JournalActa Materialia
Volume78
DOIs
StatePublished - 1 Oct 2014
Externally publishedYes

Keywords

  • Hydrogen diffusion
  • Hydrogen embrittlement
  • In situ
  • Iron
  • Neutron tomography

ASJC Scopus subject areas

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

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