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MM: Fachverband Metall- und Materialphysik

MM 20: Topical Session: Interface-dominated phenomena - Diffusion

MM 20.3: Vortrag

Dienstag, 17. März 2020, 11:00–11:15, IFW A

Development of a copper–nickel embedded-atom potential for a systematic study of grain boundary segregation and grain boundary formation energy — Felix Fischer and •Sebastian Eich — Institut für Materialwissenschaft, Universität Stuttgart

In this atomistic study [1] on the copper–nickel system, a new embedded-atom alloy potential between copper and nickel is fitted to experimental data on the mixing enthalpy. The resulting phase boundaries of the new potential are in very good agreement with a recent CALPHAD prediction. Using this new potential, a high angle symmetrical tilt Σ 5 grain boundary (GB) is chosen for a systematic investigation of equilibrium GB segregation in the semi-grandcanonical ensemble at temperatures from 400 K to 800 K. Applying thermodynamically accurate integration techniques, the GB formation energy is calculated exactly and as an absolute value for every temperature and composition.

Eventually, the thermodynamically unambiguous GB solute excess , obtained from the simulations, is fitted to a recently proposed analytical model for interface segregation [2]. Based on a composition-dependent model curve of the energy of segregation, the solute excess can be described excellently over the entire composition range for all investigated temperatures.

[1] F. Fischer, G. Schmitz, and S. M. Eich, Acta Mater. 176, 220 (2019)

[2] T. Krauß, S. M. Eich, Acta Mater. (submitted)