The effect of cooling rates on the apparent fragility of Zr-based bulk metallic glasses
- Chair for Metallic Materials, Saarland University, Campus C6.3, D-66123 Saarbruecken (Germany)
We investigate the behavior of the kinetic fragility parameter D* as different cooling rates are applied to samples of the Zr{sub 57}Cu{sub 15.4}Ni{sub 12.6}Al{sub 10}Nb{sub 5} and Zr{sub 58.5}Cu{sub 15.6}Ni{sub 12.8}Al{sub 10.3}Nb{sub 2.8} bulk metallic glass formers. The glassy samples are heated into the supercooled liquid region using differential scanning calorimetry (DSC) and cooled back into the glassy state with sets of different cooling rates, q{sub C}. The shifts in the glass transition are measured by determining the onset glass transition temperature, T{sub g}{sup onset}, as well as the limiting fictive temperature, T{sub f}{sup '}, upon reheating with a set of heating rates, q{sub H}. We then model the data by assuming a Vogel-Fulcher-Tammann-type behavior in the structural relaxation time, {tau}, and observe an apparent increase in the kinetic fragility parameter for slower cooling rates. These results show that fragilities calculated from DSC scans, where q{sub H}=q{sub C} are in good agreement with those from equilibrium viscosity data recently obtained by three-point beam-bending.
- OSTI ID:
- 21476319
- Journal Information:
- Journal of Applied Physics, Vol. 107, Issue 12; Other Information: DOI: 10.1063/1.3452381; (c) 2010 American Institute of Physics; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM ALLOYS
BENDING
CALORIMETRY
COPPER ALLOYS
DEUTERIUM IONS
HEATING RATE
METALLIC GLASSES
NICKEL ALLOYS
NIOBIUM ALLOYS
RELAXATION TIME
SUPERCOOLING
TRANSITION HEAT
TRANSITION TEMPERATURE
VISCOSITY
VITRIFICATION
ZIRCONIUM ALLOYS
ALLOYS
CHARGED PARTICLES
COOLING
DEFORMATION
ENTHALPY
IONS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT ALLOYS