Comments on DTA/DSC Methods for Estimation of Crystal Nucleation Rates in Glass-Forming Melts

AbstractThe effect of fluid flow on crystal nucleation in supercooled liquids is not well understood. The variable density and temperature gradients in the liquid make it difficult to study this under terrestrial gravity conditions. Nucleation experiments were therefore made in a microgravity environment using the Electromagnetic Levitation Facility on the International Space Station on a bulk glass-forming Zr57Cu15.4Ni12.6Al10Nb5 (Vit106), as well as Cu50Zr50 and the quasicrystal-forming Ti39.5Zr39.5Ni21 liquids. The maximum supercooling temperatures for each alloy were measured as a function of controlled stirring by applying various combinations of radio-frequency positioner and heater voltages to the water-cooled copper coils. The flow patterns were simulated from the known parameters for the coil and the levitated samples. The maximum nucleation temperatures increased systematically with increased fluid flow in the liquids for Vit106, but stayed nearly unchanged for the other two. These results are consistent with the predictions from the Coupled-Flux model for nucleation.

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Crystal nucleation and glass-forming ability of CuZr in a containerless state

Materials Science and Engineering ◽

10.1016/0025-5416(88)90030-4 ◽

1988 ◽

Vol 97 ◽

pp. 147-151 ◽

Cited By ~ 47

Author(s):

F. Gillessen ◽

D.M. Herlach

Keyword(s):

Glass Forming Ability ◽

Crystal Nucleation ◽

Glass Forming

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The Effect of Solute on the homogeneous Crystal Nucleation Frequency in Metallic Melts

MRS Proceedings ◽

10.1557/proc-9-603 ◽

1981 ◽

Vol 9 ◽

Author(s):

C.V. Thompson ◽

F. Spaepen

Keyword(s):

Regular Solution Model ◽

Solute Concentration ◽

Crystal Nucleation ◽

Qualitative Comparison ◽

Glass Forming ◽

Nucleation Frequency ◽

Homogeneous Crystal ◽

Complete Calculation ◽

Metallic Melts ◽

Approximate Expressions

ABSTRACTWe have made a complete calculation that extends the classical theory for crystal nucleation in pure melts to binary alloys. Using a regular solution model, we have developed approximate expressions for the free energy change upon crystallization as a function of solute concentration. They are used, together with model-based estimates of the interfacial tension, to calculate the nucleation frequency. The predictions of the theory for the maximum attainable undercooling are compared with existing experimental results for non-glass forming alloys. The theory is also applied to several easy glass-forming alloys (Pd-Si, Au-Si, Fe-B) for qualitative comparison with the present experimental experience on the ease of glass formation, and for assessment of the potential for formation of the glass in bulk.

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Crystal Nucleation and Glass-forming Ability of Cu–Zr in a Containerless State

Rapidly Quenched Metals 6 ◽

10.1016/b978-1-85166-971-4.50032-3 ◽

1988 ◽

pp. 147-151

Author(s):

F. GILLESSEN ◽

D.M. HERLACH

Keyword(s):

Glass Forming Ability ◽

Crystal Nucleation ◽

Glass Forming

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