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Struktur und Dynamik Poster: Mi., 14:00–16:30 M-P163
Diffusion in Al4Ni melts, by inelastic neutron scattering
Sebastian Stüber 1 , Andreas Meyer 1 , Tobias Unruh 2
1 Deutsches Zentrum für Luft und Raumfahrt, Institut für Raumsimulation, 51170 Köln
– 2 Forschungsneutronenquelle Heinz Maier-Leibnitz, TU München
We report on inelastic neutron scattering measurements on Al4Ni melts with different
isotopic compositions. The experiments were performed at the new time-of-flight
instrument of the neutron source Heinz Maier-Leibnitz in Garching, yielding an exceptionally
good signal-to-background ratio.
AlNi melts exhibit a strong non-linear dependence of the Ni self diffusion on stoichiometric
composition. By measuring Al4Ni samples with three different Ni isotopic
compositions (natural Ni, 58 Ni, and 60 Ni), we are able to derive the three partial structure
factors. The amplitude as well as the time scale of diffusive atomic motion exhibit
a strong dependence on coherent, respectively incoherent contributions to scattering,
and secondly, their oscillations are in phase with the static structure factor. This
data set allows a detailed investigation of the diffusion mechanism in AlNi melts. The
experimental results are compared with Molecular Dynamics computer simulations.