Scope for producing supercooled melts by a dynamic method
There are various ways of making supercooled melts by rapid cooling. The substance is transferred to a temperature range well below the melting point T /sub m/ , where crystallization is retarded by the high viscosity. By increasing the cooling rate in the supercooling appropriately, one can attain a finely crystalline or amorphous state for any material. High cooling rates are attained in all the methods by using small thicknesses of molten metal in contact with a cold substrate. An essentially different way of obtaining supercooled states is to melt the material at a shock-wave front and cool it in the decompression wave behind it. The cooling rate in this case can be as high as 10/sup 100/K/sec, which is above the record levels attained in traditional methods. However, the course of the isentropic curves and melting ones for some materials is such that the substance melting at the shockwave front remains liquid on decompression. Therefore, the use of dynamic pressures to produce supercooled states amounts virtually to the preparation of thin layers. The high cooling rates in these are produced on account of the small thicknesses, as in traditional methods.
- OSTI ID:
- 5078127
- Journal Information:
- Combust., Explos. Shock Waves (Engl. Transl.); (United States), Vol. 19:5; Other Information: Translated from Fizika Goreniya i Vzryva, Vol. 19, No. 5, pp. 145-149, September-October, 1983
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CRYSTALLIZATION
COOLING
SILICON
MELTING
SHOCK WAVES
CRYSTAL-PHASE TRANSFORMATIONS
CRYSTALLOGRAPHY
DYNAMICS
MELTING POINTS
MICROSTRUCTURE
MONOCRYSTALS
PRESSURE DEPENDENCE
X-RAY DIFFRACTION
COHERENT SCATTERING
CRYSTAL STRUCTURE
CRYSTALS
DIFFRACTION
ELEMENTS
MECHANICS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SCATTERING
SEMIMETALS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
360602* - Other Materials- Structure & Phase Studies