Graphitization Stress in Polycrystalline Carbon as an Origin of Dislocations

Journal Article · Mon Aug 15 04:00:00 EDT 1960 · Journal of the Physical Society of Japan

DOI:https://doi.org/10.1143/JPSJ.15.1373· OSTI ID:4162857

Tsuzuku, Takuro

When a polycrystalline carbon is heat-treated for graphitization, large thermal stress is produced owing to the interference of the extremely anisotropic expansion of each crystallite. The stress of this kind is expected to promote the rearrangement of the crystallites, directly or indirectly, from the so-called turbostratic structure to the tri-dimensional graphite lattice. The stress analysis was made on each of the spherical and the cylindrical (filamentarily textured) polycrystals in which the carbon crystallites are aligned with the basal planes parallel to the external surface. These two models aecommodate to the structure of pyrolytic carbon particle and to that of fibrous soft coke, respectively. It is shown that in either of these two cases abcut 3 x 10¹⁰ dynes/cm² tension in alpha -direction and about 0.9 x 10¹⁰ dynes/cm² compression in c-direction can be produced by heat treatment at 2500 deg C, which are enough to buckle the crystal lattice at the stress concentrations of 5 to 20 times snd may lead to the generatio of dislocations. From the corresponding strain distribution curves, the criterion on the stress relaxation by these dislocations was determined in connection with the crystallite size, which may give a measure of distinction between the so-called soft and hard carbons.

• Research Organization: Nihon Univ., Tokyo
• Sponsoring Organization: USDOE
• NSA Number: NSA-14-023332
• OSTI ID: 4162857
• Journal Information: Journal of the Physical Society of Japan, Journal Name: Journal of the Physical Society of Japan Journal Issue: 8 Vol. 15; ISSN 0031-9015
• Publisher: Physical Society of Japan
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
CARBON
CRYSTALS
CYLINDERS
DIAGRAMS
DIFFUSION LENGTH
DISPERSIONS
EXPANSION
FIBERS
GRAPHITE
HEAT TREATMENTS
INTERACTIONS
LATTICES
MEASURED VALUES
NUMERICALS
PARTICLES
PRODUCTION
PYROLYSIS
QUANTITY RATIO
SPHERES
STRESSES
SURFACES
TENSILE PROPERTIES
THERMAL STRESSES
TURBULENCE