Berlin 2008 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 10: SYM Phase Transformations in Metallic Melts IV

MM 10.2: Vortrag

Montag, 25. Februar 2008, 16:45–17:00, H 1058

Structure and dynamics of liquid Ni₃₆Zr₆₄ — •Dirk Holland-Moritz¹, Oliver Heinen¹, Andreas Meyer¹, Sebastian Stüber², Thomas Voigtmann¹, Tobias Unruh³, and Thomas Hansen⁴ — ¹Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany — ²Physik Department E13, Technische Universität München, 85747 Garching, Germany — ³Forschungsneutronenquelle Heinz Maier Leibnitz (FRM II), Technische Universität München, 85747 Garching, Germany — ⁴Institut Laue-Langevin, 38042 Grenoble, France

We investigated the atomic dynamics and the static structure factor of Ni₃₆Zr₆₄ melts. To undercool the liquids below the melting temperature and to avoid reactions with crucible materials, the melts are containerlessly processed under high purity conditions by electromagnetic levitation. This technique is combined with quasielastic neutron scattering at the time of flight spectrometer TOFTOF of the FRM II and with elastic neutron scattering at the diffractometer D20 of the ILL. Partial static structure factors have been derived via isotopic substitution. From the quasielastic neutron scattering studies the Ni self-diffusivity is determined. The partial static structure factors indicate a chemical short-range order in liquid Ni₃₆Zr₆₄ and a topological short-range order that is different from the icosahedral short-range order found in most other metallic melts. The experimental results are discussed in the framework of mode coupling theory. We thank Deutsche Forschungsgemeinschaft for funding within the priority programme 1120 under contract Nos. HO1942/6-3 and ME1958/2-3.