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Thermosolutal convection during dendritic solidificationThis paper presents a mathematical model for directional solidification of a binary alloy including a dendritic region underlying an all-liquid region. It is assumed initially that there exists a nonconvecting state with planar isotherms and isoconcentrates solidifying at a constant velocity. The stability of this system has been analyzed and nonlinear calculations are performed that show the effect of convection in the solidification process when the system is unstable. Results of calculations for various cases defined by the initial temperature gradient at the dendrite tips and varying strength of the gravitational field are presented for systems involving lead-tin alloys. The results show that the systems are stable for a gravitational constant of 0.0001 g(0) and that convection can be suppressed by appropriate choice of the container's size for higher values of the gravitational constant. It is also concluded that for the lead-tin systems considered, convection in the mushy zone is not significant below the upper 20 percent of the dendritic zone, if al all.
Document ID
19890038124
Document Type
Conference Paper
Authors
Heinrich, J. C.
(Arizona Univ. Tucson, AZ, United States)
Nandapurkar, P.
(Arizona Univ. Tucson, AZ, United States)
Poirier, D. R.
(Arizona, University Tucson, United States)
Felicelli, S.
(Arizona Univ. Tucson, AZ, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1989
Subject Category
Materials Processing
Report/Patent Number
AIAA PAPER 89-0626
Funding Number(s)
CONTRACT_GRANT: NAG3-723
Distribution Limits
Public
Copyright
Other
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