Berlin 2024 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 61: Liquid and Amorphous Materials III
MM 61.3: Vortrag
Donnerstag, 21. März 2024, 16:00–16:15, C 243
X-ray photon correlation spectroscopy on metallic glass formers under non-isothermal temperature scan conditions — Maximilian Frey1, •Ralf Busch1, and Eloi Pineda2 — 1Chair of Metallic Materials, Saarland University, Campus C6.3, 66123 Saarbrücken, Germany — 2Department of Physics, Institute of Energy Technologies, Universitat Politècnica de Catalunya - BarcelonaTech, 08019 Barcelona, Spain
Using high flux synchrotron radiation (ESRF, ID10), we study a Pt-based metallic glass former via X-ray photon correlation spectroscopy (XPCS) upon temperature scanning through the glass, glass transition and supercooled liquid (SCL). In the equilibrium SCL, the obtained intensity autocorrelation functions, g2, are well-described by a conventional Kohlrausch-William-Watts (KWW) model. Yet, in the glass and especially the glass transition region, this approach fails. Instead, we demonstrate that a multiplication of two KWW functions allows to describe the complex decay shape. Within the glass transition region, the fit parameters of the two separate KWW fits decouple massively. While one KWW component models the compressed shape of glass-typical non-equilibrium dynamics, the other fit maintains stretched liquid-like characteristics. We demonstrate that the compressed decay can be likely addressed to ballistic-like atomic motions while the stretched component apparently reflects (sub-)diffusive atomic motions, which are both superimposed in the non-equilibrium.
Keywords: Metallic glasses; X-ray photon correlation spectroscopy; Liquid dynamics; Fragility; Glass transition