SKM 2021 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 7: Topical Session Interface-Dominated Phenomena - Segregation and Embrittlement
MM 7.4: Vortrag
Mittwoch, 29. September 2021, 12:15–12:30, H8
Atomistic Insight into Hydrogen Trapping at MC/BCC-Fe Phase Boundaries: The Role of Local Atomic Environment — •Boning Zhang1,2, Jie Su2, Maoqiu Wang2, Zhenbao Liu2, Zhigang Yang1, Matthias Militzer3, and Hao Chen1 — 1Tsinghua University, Beijing, China — 2Central Iron and Steel Research Institute, Beijing, China — 3The University of British Columbia, Vancouver, Canada
A physical understanding of hydrogen trapping at microstructural defects such as grain boundaries (GBs) and phase boundaries (PBs) is vitally important for the design of hydrogen embrittlement (HE) resistant metals. As compared with GBs, the mechanism of hydrogen trapping at PBs is rather unclear due to the complex atomic environment. We perform systematic density functional theory (DFT) calculations to reveal the origin of hydrogen trapping at PBs between body centered cubic (BCC)-Fe and NaCl-type carbides (MCs). We found hydrogen trapping energetics at MC/BCC-Fe PBs depend not only on local volume dilation of the trapping sites, but also on the local atomic environment. An array of descriptors such as lattice strain, geometric volume, and charge density, which have been proven to effectively predict hydrogen trapping at GBs, fail to quantify hydrogen trapping at MC/BCC-Fe PBs. We analyzed the electronic interactions at PBs and found that they are closely related to hydrogen binding energies, and the Bader volume of hydrogen is a universal descriptor for assessing trapping energetics at PBs. This study provides a new insight into hydrogen trapping at microstructural defects.