Regensburg 2010 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 9: HV Faupel
MM 9.1: Hauptvortrag
Montag, 22. März 2010, 14:00–14:30, H16
Dynamic arrest in multicomponent glass forming alloys — •Franz Faupel1, Alexander Bartsch1, Klaus Rätzke1, and Andreas Meyer2 — 1Institut für Materialwissenschaft - Materialverbunde, Technische Fakultät, Christian-Albrechts- Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany — 2Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
We report radiotracer diffusivities in Pd- and Zr-based melts, presenting for the first time a complete set of data for all components over the whole relevant temperature range. While a vast decoupling of more than 4 orders of magnitude is observed between the diffusivity of Pd and of the smaller components, at the glass transition temperature Tg, the diffusivities of all components merge close to the critical temperature Tc of mode coupling theory. For Pd, the Stokes-Einstein relation holds in the whole range investigated encompassing more than 14 orders of magnitude suggesting the formation of a slow subsystem as a key to glass formation. In multicomponent Zr-based melts, dynamic heterogeneities and a slow Zr subsystem even exist in the equilibrium melt far above Tc.