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The influence of acceleration forces on dendritic growth and grain structureThe results of experiments on the tin-15 wt pct lead system are presented, showing the effects on microstructure of solidification in the presence of acceleration forces from 0.0001 to 5 g for three cooling rates. An increase in the acceleration level is shown to drive fluid flow and cause dendrite remelting, fragmentation, and macrosegregation. The cooling rate impacts the final structure through its control of dendrite arm spacings and permeability to fluid flow. At the low (0.0001 g) acceleration, dendrite arm spacings deviated from the predicted relationship to cooling rate. An explanation for this anomaly is given which considers the temperature and concentration gradients in the low-gravity environment.
Document ID
19820052786
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Johnston, M. H.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Parr, R. A.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 10, 2013
Publication Date
March 1, 1982
Publication Information
Publication: Metallurgical Transactions B - Process Metallurgy
Volume: 13B
Subject Category
Metallic Materials
Accession Number
82A36321
Distribution Limits
Public
Copyright
Other

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