Regensburg 2004 – wissenschaftliches Programm

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M: Metallphysik

M 11: Hauptvortrag Stefan Müller

M 11.1: Hauptvortrag

Dienstag, 9. März 2004, 09:30–10:00, H16

Ab-initio thermodynamics of metal alloys: From the atomic to the mesoscopic scale — •Stefan Müller — Universität Erlangen-Nürnberg, Lehrstuhl für Festkörperphysik, Staudtstr. 7, D-91058 Erlangen

The combination of density functional theory calculations (DFT) with Cluster Expansion methods (CE) gives access to both huge parameter-spaces (e.g. for ground-state searches) and systems containing more than a million of atoms (e.g. for microstructure studies). It will be shown how, together with Monte-Carlo simulations, this ansatz can be applied to study alloy properties which possess a delicate temperature-dependence like mixing enthalpies, short-range order or microstructure evolution without any empirical parameters, but with an accuracy that a quantitative comparison with experimental data becomes possible. Regarding microstructures I will focus on so-called coherent precipitates whose size-shape relations can be of technical relevance in alloys like Al-Li, Al-Zn, or Al-Cu. The presented methods will be extended to alloy surfaces in order to investigate ordering at surfaces and surface segregation, i.e. the deviation of the alloy’s composition in the near-surface region compared to the bulk.