Regensburg 2025 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 21: Interface Controlled Properties, Nanomaterials and Microstructure Design

MM 21.5: Vortrag

Mittwoch, 19. März 2025, 16:45–17:00, H22

Atomistic computer simulations of the influence of grain boundary phases on segregation — •Tobias Brink, Dongjin Kim, and Gerhard Dehm — Max Planck Institute for Sustainable Materials, Düsseldorf, Germany

The properties of polycrystalline materials are often strongly affected by grain boundary (GB) segregation. Segregation energies, in turn, strongly depend on the available segregation sites and their atomic environments in the GB. At the atomic level, however, GBs are not only distinguished by their macroscopic, crystallographic parameters: different GB phases (or “complexions”) can coexist even along the same GB and consequently affect available segregation sites. Similar as for bulk phases, the equilibrium atomic structure and chemistry of GBs changes based on temperature, pressure, concentration, chemical potential, etc.

Here, we investigate Ag segregation to [111] tilt GBs in Cu with hybrid molecular dynamics/Monte Carlo computer simulations using EAM potentials. These GBs are of interest because they exhibit two GB phases, “pearl” and “domino”. Depending on the misorientation, either the pearl or the domino phase can more easily accommodate Ag segregants. As a consequence, the GB phases not only display distinct segregation behavior, but the stability of the GB phases is now also a function of the Ag excess concentration. An outlook on the effects of other segregants will be given and comparisons to experimental results will be discussed.

Keywords: Grain boundary phases; Segregation; Molecular Dynamics; Monte Carlo