Regensburg 2022 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 15: Hydrogen in Materials: Hydrogen Effects
MM 15.1: Talk
Tuesday, September 6, 2022, 11:45–12:00, H46
Atomistic study of hydrogen behavior in bcc and fcc Fe in presence of crystal defects — •Daria Smirnova1, Sergei Starikov2, Tapaswani Pradhan2, Ralf Drautz2, and Matous Mrovec2 — 1Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany — 2Ruhr University Bochum, ICAMS, Bochum, Germany
We apply atomistic simulations to consider hydrogen behavior in Fe in presence of the given lattice distortions, namely, crystal defects or lattice expansion/compression due to applied stresses. Simulations are based on a new interatomic potential developed by the authors of current work. Firstly, we consider segregation of hydrogen on typical defects of different complexity: from vacancies to grain boundaries (GBs). Estimated segregation energies obtained for different types of GBs generally agree with the existing DFT data. Moreover, performed classical atomistic simulations give information on several types of GBs, which, due to their complex structure and considerable model size, are inaccessible for ab initio modeling. High-temperature simulations of H diffusion in the presence of GBs also show that for bcc Fe hydrogen diffusion coefficient in the GB is much lower than in bulk. The same type of study is carried out for fcc Fe. Also, we discuss variations in zero-temperature hydrogen migration barriers in bulk bcc Fe with applied stress and compare them with the results of the finite-temperature H diffusion simulations. We see that while the variations in the lattice parameter change hydrogen migration barrier, they give no significant impact on the finite-temperature hydrogen diffusion.