Peculiarity of hydrogen absorption in duplex steels: Phase-selective lattice swelling and stress evolution

Thomas Pogrielz, Matthias Eichinger, Adam Weiser, Juraj Todt, Anton Hohenwarter, Atacan Ascii, Baran Sarac, Dominik Brandl, Gerald Ressel, Milan Jary, Antonin Dlouhý, Gregor Karl Mori, Jozef Keckes

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Electrochemical hydrogen absorption in duplex steels is not fully understood. In this work, an in-situ synchrotron cross-sectional X-ray micro-diffraction analysis is performed on steel with comparable phase fractions of ferrite and austenite, coupled with electrolytic hydrogen charging. The results reveal that charging with a constant current density of 10 mA/cm² for 5 h leads to expanding the austenitic lattice to a depth of approximately 250 µm, up to ≥0.15 %. In contrast, the lattice parameter of the ferrite phase remains unchanged during this process. As the austenite expansion progresses, it generates different amounts of equivalent in-plane compressive stresses, which amount to approximately -150 and -450 MPa in the austenite and ferrite phases at the sample surface, respectively. Using a finite element model of grain interaction, this difference is qualitatively interpreted by mutual mechanical constraints between ferrite and austenite, as well as between the hydrogen-charged surface layer and the underlying material.
Original languageEnglish
Article number116142
Number of pages7
JournalScripta Materialia
Issue number15 July
Publication statusE-pub ahead of print - 27 Apr 2024

Bibliographical note

Publisher Copyright: © 2024 The Author(s)


  • Duplex steel
  • Electrochemistry
  • Hydrogen embrittlement
  • Residual stress
  • Synchrotron x-ray diffraction

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