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Record 1 of 34126
Particle Engulfment and Pushing By Solidifying Interfaces
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Author and Affiliation:
Stefanescu, Doru M.(Alabama Univ., Dept. of Metallurgy and Materials Engineering, Tuscaloosa, AL United States)
Mukherjee, Sundeep(Alabama Univ., Dept. of Metallurgical Engineering, Tuscaloosa, AL United States)
Juretzko, Frank Robert(Alabama Univ., Dept. of Metallurgical Engineering, Tuscaloosa, AL United States)
Catalina, A.drian V.(Universities Space Research Association, Huntsville, AL United States)
Sen, Subhayu(Universities Space Research Association, Huntsville, AL United States)
Curreri, P. A.(NASA Marshall Space Flight Center, Huntsville, AL United States)
Abstract: The phenomenon of interaction of particles with solid-liquid interfaces (SLI) has been studied since the mid 1960's. While the original interest stemmed from geology applications (frost heaving in soil), researchers soon realized that fundamental understanding of particles behavior at solidifying interfaces might yield practical benefits in other fields, including metallurgy. In materials engineering the main issue is the location of particles with respect to grain boundaries at the end of solidification. Considerable experimental and theoretical research was lately focused on applications to metal matrix composites produced by casting or spray forming techniques, and on inclusion management in steel. Another application of particle SLI interaction is in the growing of Y1Ba2Cu3O(7-delta) (123) superconductor crystals from an undercooled liquid. The oxide melt contains Y2Ba1Cu1O5 (211) precipitates, which act as flux pinning sites. The experimental evidence on transparent organic materials, as well as the recent in situ observations on steel demonstrates that there exist a critical velocity of the planar SLI below which particles are pushed ahead of the interface, and above which particles are engulfment. The engulfment of a SiC particle in succinonitrile is exemplified. However, in most commercial alloys dendritic interfaces must be considered. Indeed, most data available on metallic alloys are on dendritic structures. The term engulfment is used to describe incorporation of a particle by a planar or cellular interface as a result of local interface perturbation, as opposed to entrapment that implies particle incorporation at cells or dendrites boundaries. During entrapment the particles are pushed in the intercellular or interdendritic regions and then captured when local solidification occurs. The physics of these two phenomena is fundamentally different.
Publication Date: Mar 01, 2001
Document ID:
20010057318
(Acquired Jul 09, 2001)
Subject Category: SOLID-STATE PHYSICS
Document Type: Conference Paper
Publication Information: Microgravity Materials Science Conference 2000; Volume 3; 556-561; (SEE 20010057302)
Contract/Grant/Task Num: NAS8-39715
Financial Sponsor: NASA Marshall Space Flight Center; Huntsville, AL United States
Organization Source: NASA Marshall Space Flight Center; Huntsville, AL United States
Description: 6p; In English; CD-ROM contains the entire Conference Proceedings presented in PDF format
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: SOLIDIFICATION; PARTICLE INTERACTIONS; LIQUID-SOLID INTERFACES; SUPERCONDUCTORS (MATERIALS); METAL MATRIX COMPOSITES; CRITICAL VELOCITY; TRANSPARENCE; PRECIPITATES; GRAIN BOUNDARIES; FORMING TECHNIQUES; FLUX PINNING
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