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MM: Fachverband Metall- und Materialphysik
MM 56: Liquid and Amorphous Metals IV
MM 56.6: Talk
Thursday, April 3, 2014, 12:45–13:00, IFW A
High-resolution laser dilatometry applied to volume equilibration phenomena in bulk metallic glasses — •Martin Luckabauer1, Uta Kühn2, Jürgen Eckert2, and Wolfgang Sprengel1 — 1Institut für Materialphysik, Technische Universität Graz, Austria — 2Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, Germany
The slowing down of molecular or atomic motion occurring at the calorimetrically determined glass transition temperature Tg upon cooling complicates the access of kinetic processes at lower temperatures. However, possible changes around or below Tg regarding the structural dynamics are believed to yield key parameters in understanding the glass transition. In this talk some insight on how to examine the equilibration processes in the far sub- Tg regime will be given applying the method of high-resolution laser dilatometry. This technique involves contactless measurements with a 2-beam Michelson laser-interferometer capable of accessing volume equilibration time constants of up to 1·106 s with a length change resolution of up to 10 nm. In addition the dynamical change of the instantaneous thermal expansion coefficient during volume equilibration can be studied simultaneously. Experimental results regarding changes in the volume equilibration processes upon approaching the glass transition from lower temperatures are presented. Moreover, the possibility of using the thermal expansion coefficient as an indication of the equilibration state of the material is discussed. Financial support by the Austrian Science Fund (FWF) is appreciated (project P22645-N20).