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the effect of solidification rate on morphological stabilityAt low solidification rates, the criterion for the onset of morphological instability parallels closely the criterion of constitutional supercooling. At somewhat larger rates of solidification, however, the results of the perturbation theory of morphological instability differ significantly from the predictions of constitutional supercooling. This arises because the critical wave length for instability decreases as solidification rate increases and thus the effects of capillarity (solid-liquid surface tension) play a strong stabilizing role. This gives rise to the concept of absolute stability, according to which the system will always be stable for a sufficiently large rate of solidification. This enhanced stabilization by capillarity is present only so long as local equilibrium is maintained at the solid-liquid interface. If the interfacial temperature drops below its equilibrium value by an amount dependent on growth rate, oscillatory morphological instabilities can occur. The differences among these various stability criteria are illustrated by means of some simple two-dimensional diagrams that should supplant the conventional plots of (temperature gradient)/(growth rate) vs. alloy concentration.
Document ID
19840020551
Document Type
Conference Paper
Authors
Sekerka, R. F.
(Carnegie-Mellon Univ. Pittsburgh, PA, United States)
Date Acquired
August 12, 2013
Publication Date
April 15, 1984
Publication Information
Publication: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the High-Speed Growth and Characterization of Crystals for Solar Cells
Subject Category
SOLID-STATE PHYSICS
Meeting Information
US-Japan Cooperative Sci. Program Seminar on Solidification Process.(Dedham, MA)
Funding Number(s)
CONTRACT_GRANT: NSF DMR-78-22462
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19840020545Analytic PrimaryProceedings of the Flat-plate Solar Array Project Research Forum on the High-speed Growth and Characterization of Crystals for Solar Cells
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