Regensburg 2025 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 36: Mechanical Properties
MM 36.2: Vortrag
Freitag, 21. März 2025, 10:30–10:45, H23
Surface structure and reactivity of Aluminium alloys studied by DFT — •Zhengqing Wei1, Inna V. Plyushchay2, Nebahat Bulut1, Florian Lehmann3, Maik Gude3, Julia Hufenbach4,5, and Sibylle Gemming1,6 — 1Inst. Physics, TU Chemnitz, Germany — 2Natl. Taras Shevchenko University of Kyiv, Ukraine — 3ILK, TU Dresden, Germany — 4IFW Dresden, Germany — 5Inst. Materials Science, TU-BA Freiberg, Germany — 6MAIN Center, TU Chemnitz, Germany.
Classically, the mechanical properties of alloys are attributed to the action of stress fields around defect sites and to their combined influence on the overall elastic moduli. The present study employs first-principles modeling to include also changes of the electronic structure and investigate the bonding, stability, and reactivity changes around impurities in the bulk and at surfaces. We focus on Al alloys with low amounts of substitutional Mg, Zr, and Si atoms. The results indicate that the electron density changes mostly within the first coordination sphere around the impurity, the bond lengths vary locally within few percent, and there exists a thermodynamic driving force for most elements to diffuse to or near surfaces or interfaces. Stable 2D surface alloy compositions in part differ from the bulk phase and exhibit an element-specific reactivity with air and polymer coatings. Modeling the adsorption of oxygen, nitrogen and the PEEK polymer from first principles gives access to modified local potentials for the classical modeling of large-scale surface and interface areas (tu-dresden.de/ing/forschung/Graduiertenkollegs/grk2868#intro).
Keywords: alloy; density functional; phase stability