TY - JOUR

T1 - Peculiarity of hydrogen absorption in duplex steels

T2 - Phase-selective lattice swelling and stress evolution

AU - Pogrielz, Thomas

AU - Eichinger, Matthias

AU - Weiser, Adam

AU - Todt, Juraj

AU - Hohenwarter, Anton

AU - Ascii, Atacan

AU - Sarac, Baran

AU - Brandl, Dominik

AU - Ressel, Gerald

AU - Jary, Milan

AU - Dlouhý, Antonin

AU - Mori, Gregor Karl

AU - Keckes, Jozef

N1 - Publisher Copyright: © 2024 The Author(s)

PY - 2024/4/27

Y1 - 2024/4/27

N2 - 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.

AB - 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.

KW - Duplex steel

KW - Electrochemistry

KW - Hydrogen embrittlement

KW - Residual stress

KW - Synchrotron x-ray diffraction

UR - https://doi.org/10.1016/j.scriptamat.2024.116142

UR - http://www.scopus.com/inward/record.url?scp=85191348338&partnerID=8YFLogxK

U2 - 10.1016/j.scriptamat.2024.116142

DO - 10.1016/j.scriptamat.2024.116142

M3 - Article

VL - 248.2024

JO - Scripta Materialia

JF - Scripta Materialia

SN - 1359-6462

IS - 15 July

M1 - 116142

ER -