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M: Metallphysik

M 6: Hauptvortrag Jürgen Horbach

M 6.1: Hauptvortrag

Montag, 8. März 2004, 14:00–14:30, H16

Computer Simulations of Transport Processes in Multicomponent Melts — •Jürgen Horbach — Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55099 Mainz

We use molecular dynamics (MD) computer simulations to investigate the atomic transport in multicomponent metallic and oxide melts. The detailed information as obtained by MD allows to elucidate the interplay between structure, dynamics and phase behavior of liquid mixtures. We present simulation results for realistic models of ion–conducting alkali silicate melts and Al–Ni alloys. These systems exhibit intermediate range order that is reflected by prepeaks in static structure factors. In Al–rich Al–Ni melts a prepeak is found due to an inhomogeneous distribution of the Ni atoms and we discuss the importance of this structure for diffusion dynamics and phase behavior. The intermediate range order in the alkali silicates provides the presence of diffusion channels for the fast alkali ion motion. The interplay of the latter channel stucture with non–trivial transport phenomena such as the mixed alkali effect in ternary alkali silicates is demonstrated. We show that many aspects of the dynamics in the considered systems can be understood by the mode coupling theory of the glass transition.