Berlin 2008 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 26: Liquid and Amorphous Metals I
MM 26.3: Vortrag
Mittwoch, 27. Februar 2008, 14:30–14:45, H 0107
Diffusion of 32P, 57Co and 103Pd in the glass-forming Pd43Cu27Ni10P20 alloy and its relation to viscosity — •Alexander Bartsch1, Klaus Rätzke1, Andreas Meyer2, and Franz Faupel1 — 1Technische Fakultät, Univ. Kiel, Kaiserstr.2, 24143 Kiel — 2Institut für Materialphysik im Weltraum, DLR Köln
Since the development of bulk metallic glasses there has been considerable research effort on these alloys. Due to the high stability against crystallisation the undercooled melt between melting temperature and caloric glass transition temperature is now accessible so that recent theories can be tested.
In general, the Stokes-Einstein equation is well accepted in the equilibrium melt of these alloys. In the supercooled melt a decoupling of diffusivity and viscosity around the critical temperature of the mode coupling theory is observed [1]. Now the 32P, 57Co and 103Pd diffusion were measured in a temperature range from 573 K up to 800 K in the Pd43Cu27Ni10P20 alloy using the radiotracer technique. We found that P and Co have similar diffusivities and compared them to viscosity data using SE equation [2]. This shows that the mobility of P and Co do not determine the viscosity in the supercooled state. Based on ongoing experiments with 103Pd we now can give an overview on the relation between diffusion and viscosity of all constituents of the alloy.
[1] V. Zöllmer, K. Rätzke, F. Faupel, A. Meyer, Phys. Rev. Lett., 90, 195502-1 (2003).
[2] A. Bartsch, K. Rätzke, F. Faupel, A.Meyer, Appl. Phys. Lett. 89, 121917 (2006)