Structural relaxation as seen by quasielastic neutron scattering on viscous Zr-Ti-Cu-Ni-Be droplets

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Details zur Publikation

Autorinnen und Autoren: Yang F, Kordel T, Holland-Moritz D, Unruh T, Meyer A
Zeitschrift: Journal of Physics: Condensed Matter
Verlag: IOP PUBLISHING LTD
Jahr der Veröffentlichung: 2011
Band: 23
Heftnummer: 25
ISSN: 0953-8984
eISSN: 1361-648X


Abstract


In bulk glass forming Zr46.8Ti8.2Cu7.5Ni10Be27.5 (Vit4) the mean Ni, Ti, and Cu self-diffusion coefficient at the liquidus is about 10(-10) m(2) s(-1). Compared with these values, diffusion coefficients derived from various reported viscosity data by rescaling them via the Stokes-Einstein relation exhibit different temperature dependence and absolute values are a factor of 5-10 smaller. This raises the question of whether a slow Zr subsystem exists in the melt at temperatures well above the liquidus temperature. Here, we address this question by studying microscopic dynamics employing quasielastic neutron scattering. We utilized containerless sample processing in a novel electrostatic levitation apparatus. This excludes reactions between samples and crucible materials and gives access to a wide momentum transfer range of about 0.2-2.6 angstrom(-1). We studied the dynamics governed by the Ni, Ti, and Cu diffusive motion as well as by collective Zr motion. At 1255 K, both correlation functions decay to zero on a timescale of about 20 ps. This shows that there is neither a decoupling between the atomic dynamics of the various components nor a slow Zr subsystem in the equilibrium melt.



FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Unruh, Tobias Prof. Dr.
Professur für Nanomaterialcharakterisierung (Streumethoden)


Einrichtungen weiterer Autorinnen und Autoren

Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)


Zitierweisen

APA:
Yang, F., Kordel, T., Holland-Moritz, D., Unruh, T., & Meyer, A. (2011). Structural relaxation as seen by quasielastic neutron scattering on viscous Zr-Ti-Cu-Ni-Be droplets. Journal of Physics: Condensed Matter, 23(25). https://dx.doi.org/10.1088/0953-8984/23/25/254207

MLA:
Yang, Fan, et al. "Structural relaxation as seen by quasielastic neutron scattering on viscous Zr-Ti-Cu-Ni-Be droplets." Journal of Physics: Condensed Matter 23.25 (2011).

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