Small atom diffusion and breakdown on Stokes-Einstein relation in the supercooled liquid state of Zr-Ti-Cu-Ni-Be alloys
- Univ. Goettingen (Germany)
- California Inst. of Tech., Pasadena, CA (United States)
- Hahn-Meitner-Inst. Berlin (Germany). Abt. Strukturforschung
Be diffusivity data in the bulk metallic glass forming alloys Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} and Zr{sub 46.7}Ti{sub 8.3}Cu{sub 7.5}Ni{sub 10}Be{sub 27.5} are reported for temperatures between 530 K and 710 K, extending up to 80 K into the supercooled liquid states of the alloys. At the glass transition temperature, T{sub g}, a change in temperature dependence of the data is observed in both alloys, and above T{sub g} the diffusivity increases faster with temperature than below. The data in the supercooled liquid can be described by a modified Arrhenius expression containing the communal entropy of the supercooled liquid and based on a diffusion mechanism suggested earlier. The comparison with viscosity data in the supercooled liquid state of Zr{sub 46.7}Ti{sub 8.3}Cu{sub 7.5}Ni{sub 10}Be{sub 27.5} reveals a breakdown of the Stokes-Einstein relation, whereas D(T) and {eta}(T) follow a relation close to van den Beukel`s. The breakdown of the Stokes-Einstein relation indicates a cooperative diffusion mechanism in the supercooled liquid state of the ZrTiCuNiBe alloys.
- Sponsoring Organization:
- Department of the Army, Washington, DC (United States); USDOE, Washington, DC (United States); Deutsche Forschungsgemeinschaft, Bonn (Germany); National Science Foundation, Washington, DC (United States)
- DOE Contract Number:
- FG03-86ER45242
- OSTI ID:
- 580897
- Report Number(s):
- CONF-961202--; ISBN 1-55899-359-2
- Country of Publication:
- United States
- Language:
- English
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