Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 14: Functional Materials - Hydrogen

MM 14.5: Vortrag

Montag, 11. März 2013, 16:45–17:00, H26

Diffusion of hydrogen in strained Fe and Ni lattices — •Davide Di Stefano, Matous Mrovec, and Christian Elsaesser — Fraunhofer Institute For Mechanics Of Materials IWM, Freiburg, Germany

A correct description for the diffusion of hydrogen in metals is prerequisite for understanding the phenomenon of hydrogen embrittlement. The H diffusion in bulk materials has been studied extensively in the past both experimentally and theoretically. Nevertheless, the knowledge of diffusion processes in distorted environments, e.g. in the vicinity of crystal defects, is still limited.

In this comparative study, we perform atomistic calculations of diffusion barriers in strained structures of Fe and Ni using accurate first-principles methods based on the density functional theory and semi-empirical tight binding. Our results show that the diffusion barriers are indeed strongly influenced by the lattice distortions and depend sensitively on the type of deformation. In addition, our analysis confirms that a proper treatment of quantum effects is crucial for a reliable theoretical determination of the diffusion barriers.