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Microstructural variations induced by gravity level during directional solidification of near-eutectic iron-carbon type alloysThe effects of gravity on the microstructure of directionally solidified near-eutectic cast irons are studied, using a Bridgman-type automatic directional solidification furnace aboard a NASA KC-135 aircraft which flies parabolic arcs and generates alternating periods of low-g (0.01 to 0.001 g, 30 seconds long) and high-g (1.8 g, 1.5 minutes long). Results show a refinement of the interlamellar spacing of the eutectic during low-g processing of metastable Fe-C eutectic alloys. Low-g processing of stable Fe-C-Si eutectic alloys (lamellar or spheroidal graphic) results in a coarsening of the eutectic grain structure. Secondary dendrite arm spacing of austenite increases in low-g and decreases in high-g. The effectiveness of low-gravity in the removal of buoyancy-driven graphite phase segregation is demonstrated.
Document ID
19870036571
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Stefanescu, Doru M.
(Alabama Univ. University, AL, United States)
Fiske, Michael R.
(Alabama, University University, United States)
Curreri, Peter A.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 13, 2013
Publication Date
July 1, 1986
Publication Information
Publication: Metallurgical Transactions A - Physical Metallurgy and Materials Science
Volume: 17A
ISSN: 0360-2133
Subject Category
Materials Processing
Accession Number
87A23845
Funding Number(s)
CONTRACT_GRANT: NAG8-469
Distribution Limits
Public
Copyright
Other

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