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A quantitative study of factors influencing lamellar eutectic morphology during solidificationThe factors that influence the shape of the solid-liquid interface of a lamellar binary eutectic alloy are evaluated. Alloys of carbon tetrabromide and hexachloroethane which serve as a transparent analogue of lamellar metallic eutectics are used. The observed interface shapes are analyzed by computer-aided methods. The solid-liquid interfacial free energies of each of the individual phases comprising the eutectic system are measured as a function of composition using a 'grain boundary groove' technique. The solid-liquid interfacial free energy of the two phases are evaluated directly from the eutectic interface. The phase diagram for the system, the heat of fusion as a function of composition, and the density as a function of composition are measured. The shape of the eutectic interface is controlled mainly by the solid-liquid and solid-solid interfacial free energy relationships at the interface and by the temperature gradient present, rather than by interlamellar diffusion in the liquid at the interface, over the range of growth rates studied.
Document ID
19820005345
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Kaukler, W. F. S.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
September 4, 2013
Publication Date
November 1, 1981
Subject Category
Metallic Materials
Report/Patent Number
NASA-TM-82451
Accession Number
82N13218
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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