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Electron Microscopical Observations of Graphite in Cast Irons

Published online by Cambridge University Press:  21 February 2011

Gary R. Purdy  and
Marc Audier
Gary R. Purdy
Affiliation:
Dept. of Metallurgy & Materials Science, McMaster University, Hamilton, Ont., Canada L8S 4L7
Marc Audier
Affiliation:
Laboratoire de Thermodynamique et Physico-Chemie Metallurgiques, E.N.S.E.E.G., B.P. 75, 38402 St. Martin d'Heres, France.
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Abstract

Graphite flakes and spheroids, extracted from rare-earth treated cast irons, have been examined using electron microscopy. Transmission microscopy has been used to investigate the defect structure of flakes and to demonstrate the concentric aromatic shell structure of spheroids. Each spheroid is shown to possess a rare-earth containing core or nucleus.

High resolution lattice images are presented as evidence for the presence of amorphous regions within flake graphite crystals. For spheroidal graphite, the lattice images indicate a greater degree of crystalline perfection. In addition, they suggest:

1) The presence of intercalation structures

2) The presence of an amorphous phase, on the graphite-iron interface, from which crystalline graphite forms at growth sites.

The implications for possible mechanisms of graphite crystallization are discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 34: Symposium – Physical Metallurgy of Cast Iron , 1984 , 13
Copyright
Copyright © Materials Research Society 1985

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References

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