Berlin 2008 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 10: SYM Phase Transformations in Metallic Melts IV
MM 10.1: Vortrag
Montag, 25. Februar 2008, 16:30–16:45, H 1058
Quasielastic Neutron Scattering on Refractory Al-Ni melts — •Sebastian Stüber1, Andreas Meyer2, Dirk Holland-Moritz2, Helena Hartmann2, and Tobias Unruh3 — 1Physik Department E13, Technische Universität München, 85747 Garching — 2Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR) 51170 Köln — 3Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universität München, 85747 Garching
In this talk we will present results of quasielastic neutron scattering at the time of flight spectrometer Tof-Tof of the FRM II used to study atomic dynamics in melts of binary Al-Ni alloys that are the basis of a large variety of high temperature applications. In order to undercool the melts deeply below the melting temperature and to avoid reactions with crucible materials, the liquids are containerlessly processed under high purity conditions by application of the electromagnetic levitation technique. Due to the containerless processing the measured dynamic structure factors are not affected by scattering from a sample container such that the quasielastic neutron scattering measurements were possible also at large momentum transfer. From the measured dynamic structure factors Ni self-diffusion coefficients are determined as a function of alloy composition and temperature. At constant temperature, the Ni self diffusivity is constant within a wide compositional range.