Regensburg 2019 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 16: Methods in Computational Materials Modelling (methodological aspects, numerics)

MM 16.7: Vortrag

Dienstag, 2. April 2019, 12:00–12:15, H45

Development of a layer-specific surface segregation model based on atomistic simulations beyond McLean — Tamara Krauß and •Sebastian Eich — Institut für Materialwissenschaft, Lehrstuhl für Materialphysik, Universität Stuttgart, Deutschland

In this atomistic study, layer-specific segregation to the surface is investigated for an exemplary (100) surface in iron–chromium alloys. Segregation is simulated in the semi-grand canonical ensemble using a thermodynamically accurate iron–chromium embedded-atom potential[1]. Through a continuous variation of the chemical potentials, the full composition range is explored in the temperature range from 400 K to 1400 K, enabling the analysis of surface segregation below and above the critical temperature of the miscibility gap. Taking the surface tensions into account, the change in surface formation energy according to the interfacial adsorption equation[2] is confirmed excellently.

With the obtained dependence of layer-specific segregation on bulk composition, it is shown that segregation cannot be described sufficiently by the single-parameter McLean model. Thus, an analytic layer-specific model of surface segregation is proposed which is capable of reproducing the simulated segregation data over the whole composition range with high accuracy. Using the modeled segregation curves, the change in formation energy can be described in an accurate manner as well.

[1] S. M. Eich, D. Beinke, and G. Schmitz, Comput. Mater. Sci. 104, 185 (2015).

[2] T. Frolov and Y. Mishin, Phys. Rev. B 85, 224106 (2012).