Berlin 2018 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 3: Topical session (Symposium MM): Hydrogen in Materials

MM 3.4: Vortrag

Montag, 12. März 2018, 12:00–12:15, H 0107

Atomistic modelling of hydrogen cosegregation at grain boundaries in iron and nickel — •Eunan J. McEniry, Tilmann Hickel, and Joerg Neugebauer — Department of Computational Materials Design, Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany

The behaviour of hydrogen at structural defects in metallic alloys is well-known to play a key role in the mechanical stability of such materials. As a result, the energetics and kinetics of hydrogen in the vicinity of grain and phase boundaries have been extensively studied via atomistic simulation, in order to understand mechanisms of hydrogen-induced decohesion. The emphasis of this work is the critical interplay of hydrogen with additional elements present in the material.

Using atomistic simulations, we have performed high-throughput calculations of the cosegregation behaviour of H, B, C, and N at selected grain boundaries in Fe and Ni. Due to the large number of configurations that must be considered, we have employed tight-binding approaches to enable the efficient and accurate description of the thermodynamics of light element cosegregation. Having obtained segregation profiles at the chosen grain boundaries as a function of bulk concentration and temperature, we employ both thermodynamic analysis as well as simulated mechanical testing to assess the impact of segregants on the structural stability of the grain boundaries.