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M: Metallphysik

M 14: Hauptvortrag Meyer

M 14.1: Hauptvortrag

Dienstag, 25. März 2003, 09:30–10:00, IFW A

Atomic transport in multicomponent melts — •Andreas Meyer — Physik Department E13, Technische Universität München

We investigate the atomic motion in viscous metallic and oxide melts with inelastic neutron scattering in order to clarify the microscopic transport mechanisms. The high-resolution energy and momentum information emerging from inelastic neutron scattering experiments allows to study the interplay between structure, viscous flow and the atomic diffusion of particular components. Results on bulk glass forming metallic melts, ion conducting oxide melts and multicomponent silicate melts (simple analog for magma) reveal non-trivial mechanisms for mass transport. In dense, hard-sphere like metallic melts the mode coupling theory of the liquid to glass transition gives a consistent description of the dynamics in the equilibrium liquid range. In other metallic and in oxide systems atomic diffusion and viscous flow decouple with increasing network character. In alkali silicate melts we find a medium range order that is relevant for the fast ion conduction pathways and the viscous flow. We discuss the common features (mode-coupling) and structurally determined differences of the atomic transport in these multicomponent melts.