Results 181 to 190 of about 5,766 (227)

Processing of undercooled melts

AIP Conference Proceedings, 1990
The undercooling of liquids is observed often, but is restricted by the catalysis of heterogeneous nucleation sites in contact with the liquid. Containerless liquid processing and liquid dispersal into fine droplets yields an effective nucleant isolation which permits a deep undercooling approaching 0.3–0.4 Tm before the onset of solidification.
J. H. Perepezko, W. P. Allen
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Solidification of undercooled metals

Materials Science and Engineering, 1984
The present investigation is concerned with the subject of undercooling (i.e., supercooling) in the case of metal alloys, taking into account the effects of undercooling on microstructure and microsegregation in alloys which solidify in a crystalline manner. Techniques for obtaining a large degree of undercooling are discussed. These techniques make it
Merton C. Flemings, Yuh Shiohara
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Undercooling of Liquid Germanium

MRS Proceedings, 1985
AbstractSmall liquid germanium (ℓ-Ge) droplets (0.3–0.5mm diameter) have been undercooled in a B2O3 flux a maximum of 415 ± 20°C below Tm before recalescence. Although the droplets undercooled to temperatures well below the temperature expected for metastable equilibrium with amorphous Ge, Taℓ, the solidified structures were always polycrystalline ...
G. Devaud, D. Turnbull
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Microstructures of undercooled germanium

Acta Metallurgica et Materialia, 1991
Abstract Liquid Ge drops (diameter 7 mm) have been undercooled 60−342±°C below Tm in dehydrated boron oxide with a cooling rate of 6°C/min. They always crystallized to the diamond cubic phase and the resulting grain size decreased with increasing undercooling. During crystallization, audible sound was emitted whenever the undercoolings were ⪸ 258°
C.F. Lau, H.W. Kui
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Microstructures of undercooled Si

Journal of Applied Physics, 1994
Molten Si was allowed to solidify isothermally at initial bulk undercoolings ΔT from 5.7 to 157 K. It was found that in addition to the 〈211〉 twin dendrites two novel dendrites were found: the 〈110〉 twin and the 〈100〉 twin free dendrite. The 〈110〉 twin dendrite has multiple twin planes, and the orientation of the twin plane is {111}.
K. K. Leung, H. W. Kui
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Undercooling in Steam Nozzles

Journal of Fluids Engineering, 1936
Abstract This paper deals primarily with the effect of wall roughness on the flow of steam in nozzles; and secondarily with drop growth and the occurrence of initial condensation. It was found that roughness of the nozzle walls caused a retardation of steam flow and resulted in the Wilson line’s occurring at the 3.2 per cent moisture ...
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The interfacial undercooling in solidification

Journal of Crystal Growth, 1997
Abstract The origin and characteristics of the undercooling at the solid/liquid interface are examined for solidification of metallic alloys in general, and of intermetallic compounds in particular. The contributions of the various components of the interfacial undercooling can be clarified using a graphical representation in terms of their ...
H. Assadi, A.L. Greer
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Nucleation and Dendritic Growth in Undercooled Melts

MRS Proceedings, 1995
ABSTRACTTechniques of containerless processing are applied to undercool and solidify metals and alloys. These techniques allow direct measurements of both the undercooling and the crystal growth velocity. Experimental results are presented for studies of nucleation of metastable crystalline phases and quasicrystals.
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Corner Formation for the Undercooled Stefan Problem

SIAM Journal on Applied Mathematics, 2001
This paper contains an extensive analysis of the development of corners in the free boundary for the one-phase undercooled Stefan problem in two and three space dimensions. A concise review of the studies of the singularities of the Stefan problem is presented in the introduction.
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Undercooling of molten silicon

Applied Physics Letters, 1985
Droplets of uncoated molten Si (0.4–0.8 mm diameter) have been undercooled 250 °C. Ge droplets of similar size have been undercooled 280 °C in a B2O3 flux. The observed nucleation onset temperatures of both Si and Ge droplets are at or below the predicted amorphous phase melting temperatures Ta1. The solidified structures were polycrystalline.
G. Devaud, D. Turnbull
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