Dresden 2017 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 34: Poster session II

MM 34.30: Poster

Dienstag, 21. März 2017, 18:30–20:30, P4

Hydrogen Diffusion in Magnesium: Influence of Grain Boundaries — •Felix Jung1, Magnus Hamm1, Jakub Cižek2, and Astrid Pundt11Institute for Material Physics, Georg-August-Universität Göttingen, Germany — 2Department of Low-Temperature Physics, Charles University, Prague, Czech Republic

Grain boundary (GB) diffusion differs from bulk diffusion in crystals. For substitutional solvents in metals, GB diffusion is several orders of magnitude faster, for interstitial solvents it can be either slower or faster, depending on the solvent concentration [1,2]. In this work the diffusion of hydrogen gas in the magnesium-hydrogen system is used as a model system. To explore the dependence of the diffusion coefficient on grain boundaries, the sample grain size is varied, thereby achieving differing grain boundary volume fractions. Additionally, the difference between the metallic magnesium and the hydride phase is studied. Magnesium thin films and ECAP treated bulk magnesium samples are characterized using optical and electron microscopy. Purity and grain structure of the bulk samples are investigated by EDX and EBSD measurements. Hydrogen gas volumetry is used to determine the diffusion behaviour in the α-regime and the hydride phase and to calculate the related diffusion coefficients. Financial support provided by the Deutsche Forschungsgemeinschaft via the projects PU131/9-2 and PU131/10-1 is gratefully acknowledged. [1]I. Kaur und W. Gust, Fundamentals of grain and interphase boundary diffusion, Stuttgart: Ziegler Press, (1989) [2]T. Muetschele and R. Kirchheim, Scripta Metallurgica 21, 135-140 and 1101-1104, (1987)

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