Nucleation-controlled solidification kinetics

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02648944· OSTI ID:237766

Perepzko, J H; Uttormark, M J ^[1]

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1. Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering

Solidification microstructures are usually classified with the respect to the growth processes responsible for the observed morphology. However, experience has demonstrated that several regimes of processing conditions can be identified in which nucleation is the determining factor in the phase selection and the evolution of the solidification microstructure. Several of these regimes are analyzed to identify the influence of nucleation on the final microstructure. In most cases, nucleation occurs by heterogeneous catalysis with competitive kinetics between different sites and product structures. The proper analysis of heterogeneous nucleation requires a clear identification and description of active catalytic sites which has been a continuing challenge for both experiments and analysis since nucleation signatures can be masked by subsequent reactions. A strategy for the systematic exploration of heterogeneous nucleation in alloys is described that yields some information about possible atomistic and dynamic effects at the catalyst/melt interface that is of theoretical and practical interest. Additionally, computer simulation studies are described that elucidate some of the atomistic features of nucleation which become increasingly important when a multiplicity of nucleation sites is observed with a hierarchy of potency.

• Sponsoring Organization: USDOE
• OSTI ID: 237766
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 3 Vol. 27; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOYS
CATALYSIS
COMPUTERIZED SIMULATION
CONVECTION
DENDRITES
EUTECTICS
GRAIN REFINEMENT
HEAT EXTRACTION
INTERFACES
LIQUID METALS
MICROSTRUCTURE
MORPHOLOGY
SOLIDIFICATION