SKM 2021 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 2: Topical Session Interface-Dominated Phemomena - Moving Interfaces / Functional Properties

MM 2.2: Vortrag

Montag, 27. September 2021, 11:30–11:45, H8

Atomistic simulation of grain boundary phases and transitions in fcc metals — •Tobias Brink and Gerhard Dehm — Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany

Grain boundaries (GBs) can be treated as interface phases (also called “complexions”) with different thermodynamic excess properties. Congruent phase transitions in pure metals—where the macroscopic GB parameters remain constant—are hard to observe experimentally, but GB phases with distinct atomic structures could recently be identified in a copper tilt GB (Meiners et al., Nature 579, 2020). It remains an open question if such phases are specific to this copper GB or a more general feature of fcc metals. Using molecular dynamics computer simulations, we investigated both Cu and Al ⟨ 111 ⟩ tilt GBs with different misorientations to verify if the copper GB phases can indeed be generalized. We furthermore used simulations with Lennard-Jones pair potentials to determine how much materials physics needs to be included in the model to recover the phases of the more realistic potentials. Recurring structural motifs appeared in all of these systems, but we found that the actual material strongly influences which phases occur and their stability. This probably excludes the possibility of deriving simple rules for the atomic structure of GB phases.

Acknowledgment: This result is part of a project that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 787446; GB-CORRELATE).