Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 9: Interfaces II: Segregation and embrittlement

MM 9.3: Vortrag

Montag, 7. März 2016, 12:15–12:30, H39

Hydrogen behaviour at structural defects in high-strength steels — •Eunan J. McEniry, Tilmann Hickel, and Jörg Neugebauer — Department of Computational Materials Design, Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf

The behaviour of hydrogen in high-strength steels is well-known to play a very significant role in the long-term stability and mechanical properties of such materials. Experimental and theoretical work has indicated that structural defects, such as grain boundaries, dislocations, nanovoids and phase boundaries between the matrix and precipitates present in the material, play the most important role in the phenomenon of hydrogen embrittlement.

Using atomistic simulations, we have examined the energetics and diffusion of hydrogen in the vicinity of such extended defects. Particular emphasis has been placed on a wide range of grain boundaries in ferrite, and on semi-coherent interfaces between ferrite and non-metallic inclusions such as TiC and TiN. Due to the large system sizes required to simulate, for example, low-symmetry grain boundaries or misfit dislocations between the matrix and inclusions, conventional ab initio simulations are no longer feasible. In this direction, we have developed scale-bridging atomistic potentials based on the tight-binding approximation, which still allow for a fully quantum-mechanical treatment of the system.