Berlin 2024 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 10: Topical Session: Hydrogen in Materials: from Storage to Embrittlement I
MM 10.1: Topical Talk
Montag, 18. März 2024, 15:45–16:15, C 130
Unraveling the impact of defect-induced phases on hydrogen embrittlement and storage — •Ali Tehranchi1, Poulami Chakraborty1,2, Marti Lopez Freixes1, Jing Rao1, Maria J Duarte Correa1, Baptiste Gault1,3, Tilmann Hickel1,4, and Jörg Neugebauer1 — 1-Max-Planck-Institut für Eisenforschung GmbH, D-40237 Düsseldorf, Germany — 2Basque Center for Applied Mathematics, Bilbao, 48009, Spain — 3-Department of Materials, Imperial College, South Kensington,London, SW7 2AZ, UK — 4Bundesanstalt für Materialforschung und -prüfung (BAM)
Establishing a hydrogen economy to reduce carbon emissions has sparked renewed interest in hydrogen embrittlement (HE) and hydrogen storage (HS) mechanisms. We examine the critical role of defect-induced hydride and metallic phases, highlighting associated challenges and opportunities. First, using ab initio thermodynamics the role of H on the relative stability of the fcc/bcc/hcp phases in steels is studied. These studies show the existence of a few atomic percent of H in retained austenite (RA) at experimentally relevant H chemical potentials. Therefore, a phase transformation of H-charged fcc to bcc will release the excess H. We discuss the interplay of H in grain/phase boundaries to assess the role of these excess H in HE. Second, the formation of nano-hydrides (NHs) in vicinity of various defects in ferritic FeCr and high-strength Al-based alloys is analyzed. NHs under indentors and around dislocations significantly alter the mechanical response of FeCr alloy. NHs in the vicinity of dislocations and micro-cracks in Al-based alloys provide new opportunities for enhancing HS.
Keywords: metal hydrides; hydrogen embrittlement; hydrogen storage; ab initio thermodynamics; retained austenite