ELECTRON MICROSCOPE STUDIES OF DISLOCATION STRUCTURES IN GRAPHITE
Dislocations in a variety of single-crystal flakes of graphite (hexagonal crystal structure) were studied by transmission electron microscopy. All the dislocations observed were parallel to the layer plane with Burgers vectors in this plane. Dislocations occurred as pairs, approximately 1000 A apart, with Burgers vectors of the type 1/3a(1010-bar) giving together a unit lattice translation of a along one of the three coplanar hexagonal axes. The area between these two partials contained a stacking fault corresponding to the rhombohedral structure discussed by Lipson & Stokes. The stacking fault energy was shown to be approximately 1/10 erg/cm/sup 2/ and to be substantially independent of temperature up to 900 deg C. Two interactions were observed; one was a direct one to form a network with extended and contracted nodes, and the other was an indirect one between dislocations on different slip planes and owing to the long-range stress fields of the dislocations. An asymmetry observed in the latter interaction can be explained by the different line tensions of edge and screw dislocations. All dislocations were glissile, and no interaction leading to sessile dislocations was found. (auth)
- Research Organization:
- Atomic Energy Research Establishment, Harwell, Berks, Eng.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-14-025991
- OSTI ID:
- 4138906
- Journal Information:
- Proc. Roy. Soc. (London), Vol. Vol: A257; Other Information: Orig. Receipt Date: 31-DEC-60
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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