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Real Time Characterization of Solid/Liquid Interfaces During Directional SolidificationA X-Ray Transmission Microscope (XTM) has been developed to observe in real time and in-situ solidification phenomenon at the solid/liquid interface. Recent improvements in the horizontal Bridgman furnace design provides real-time magnification (during solidification) up to 12OX. The increased magnification has enabled for the first time the XTM imaging of real-time growth of fibers and particles with diameters of 3-6 micrometers. Further, morphological transitions from planar to cellular interfaces have also been imaged. Results from recent XTM studies on Al-Bi monotectic system, Al-Au eutectic system and interaction of insoluble particles with s/I interfaces in composite materials will be presented. An important parameter during directional solidification of molten metal is the interfacial undercooling. This parameter controls the morphology and composition at the s/I interface. Conventional probes such as thermocouples, due to their large bead size, do not have sufficient resolution for measuring undercooling at the s/I interface. Further, the intrusive nature of the thermocouples also distorts the thermal field at the s/I interface. To overcome these inherent problems we have recently developed a compact furnace which utilizes a non-intrusive technique (Seebeck) to measure undercooling at the S/I interface. Recent interfacial undercooling measurements obtained for the Pb-Sn system will be presented. The Seebeck measurement furnace in the future will be integrated with the XTM to provide the most comprehensive tool for real time characterization of s/I interfaces during solidification.
Document ID
19990064335
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Sen, S.
(Universities Space Research Association Huntsville, AL United States)
Kaukler, W. K.
(Alabama Univ. Huntsville, AL United States)
Curreri, P. A.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Peters, P.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1997
Subject Category
Metallic Materials
Meeting Information
Meeting: Advanced Materials and Processes
Location: Honolulu, HI
Country: United States
Start Date: July 12, 1998
End Date: July 16, 1998
Distribution Limits
Public
Copyright
Other

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