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MM: Fachverband Metall- und Materialphysik
MM 39: Computational Materials Modelling V
MM 39.2: Talk
Thursday, March 17, 2011, 16:30–16:45, IFW A
Hydrogen solution enthalpies derived from first principles: Chemical trends along the series of transition metals — •Ugur Aydin1, Sixten Boeck2, Tilmann Hickel1, and Jörg Neugebauer1 — 1Max-Planck Institut für Eisenforschung — 2Gemmantics IT-Consulting
Since the mid-19th century it has been known that some transition metals (TM) can absorb significant amounts of hydrogen, whereas others cannot. Since the presence of this interstitial atom can lead to serious materials failures, the energetics and dynamics of hydrogen in TMs are of critical importance in state-of-the-art materials design. Most of the previous studies, considering the hydrogen solubility for a larger number of TMs, rely on experimental observations and/or semi-empirical models. However, the ability of these models to provide a deeper understanding and insight into the decisive underlying mechanisms involved in hydrogen-solubility is limited. In our work, we therefore employed ab initio calculations to systematically investigate the mechanical and chemical mechanisms governing hydrogen solution in a complete set of TM under comparable conditions. The solution enthalpy for H in the high symmetry interstitial sites of TMs has been calculated consistently assuming various crystallographic / magnetic structures. For the data management a sophisticated automatic database has been developed. The analysis of this complete set of data allowed us to detect an universal dependence of the H solution enthalpy on the crystal lattice constant. Further a material dependent interplay of chemical and strain contributions has been found.