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MM: Fachverband Metall- und Materialphysik
MM 4: Liquid and Amorphous Metals I: Glassy dynamics
MM 4.2: Vortrag
Montag, 7. März 2016, 10:30–10:45, H52
Distinct dynamical regimes in a gold-based metallic glass revealed by X-ray photon correlation spectroscopy (XPCS) — •Simon Hechler1, Beatrice Ruta2, Zach Evenson3, Moritz Stolpe1, William Hembree1, Isabella Gallino1, and Ralf Busch1 — 1Lehrstuhl für Metallische Werkstoffe, Universität des Saarlandes, Saarbrücken — 2ESRF, Grenoble — 3Heinz Maier-Leibnitz-Zentrum, TU München, Garching
Although structural relaxation is a universal feature of glasses, the atomic-level processes involved still remain a puzzling mystery. XPCS has emerged as a novel technique for studying the microscopic dynamics of non-equilibrium condensed matter, as it enables the investigation of the structural relaxation time by resolving the translational atomic motion in non-equilibrium materials as metallic glasses. Using XPCS experiments, we follow the equilibration from the glass into the supercooled liquid of a gold- based metallic glass. The as-cast alloy shows different dynamical regimes as it approaches the glass transition.At low temperature, the relaxation time appears to be almost temperature independent. Upon heating, closer to the glass transition, the glass shows highly temperature dependent dynamics. In the supercooled liquid region, the material changes the equilibrium dynamics upon cooling to a significantly stronger dynamic behavior, without freezing to a glass. Such crossovers in the dynamics have not been observed in XPCS studies before and suggest the existence of complex structural relaxation mechanisms in this metallic glass forming material.