Coarsening of eutectic fiber composites during cooling from the eutectic temperature

Journal Article · Wed Oct 01 04:00:00 EDT 1975 · Metall. Trans., A; (United States)

DOI:https://doi.org/10.1007/BF02646860· OSTI ID:5000113

Garmong, G ^[1]; Courtney, T H

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1. Rockwell International Science Center, Thousand Oaks, CA

Coarsening and microstructural changes, which occur on cooling from the eutectic temperature, were experimentally studied in Al--Al/sub 3/Ni eutectic fiber composites solidified at rates of 0.8, 5.0 and 32.5 cm per h. At the two higher growth rates, changes in fiber density on the order of 10 percent were observed between the solid-liquid interface and positions 2.0 cm from the interface. At the low growth rate the surface roughness of the as-grown fiber was noticeably decreased during cooling from the eutectic temperature. Theoretical expressions relating the change in average fiber radius or fiber density as a function of position were developed in terms of the solidification conditions, growth rate and temperature gradient, as well as the usual kinetic and thermodynamic factors influencing coarsening. The model was combined with independently obtained isothermal coarsening data to compare the experimentally observed extent of coarsening with that predicted. The predictions of the model agreed qualitatively with the data on the effect of growth rate on coarsening, but the absolute extent of coarsening was greater than that predicted from the isothermal studies. (auth)

• OSTI ID: 5000113
• Journal Information: Metall. Trans., A; (United States), Journal Name: Metall. Trans., A; (United States) Vol. 6A:10; ISSN MTTAB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360302* -- Composite Materials-- Structure & Phase Studies-- (-1987)
ALUMINIUM
ALUMINIUM COMPOUNDS
ALUMINIUM NITRIDES
COMPOSITE MATERIALS
COOLING
CRYSTAL GROWTH
CRYSTAL STRUCTURE
ELEMENTS
EUTECTICS
FILAMENTS
METALS
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
PHASE TRANSFORMATIONS
PNICTIDES
SOLIDIFICATION