Abstract
The structural factors determining the change in Young's modulus of polycrystalline carbon materials based on fired coke (type ARV) and unfired coke (type MPG) in relation to treatment temperature t in the 1000–3200°C range were investigated. The microstructure of the specimens was characterized by the density and coefficient of coherence, which was determined from the ratio of the electrical conductivity of the material to the electrical conductivity of its porosity-free volumes. The degree of perfection of the layers of specimens with a graphitic structure was determined from the magnetic resistance. It was established that the change in Young's modulus in this range of treatment temperatures is determined by the change in Young's modulus of the porosity-free volumes E0 ∼ c44 and in the coefficient of coherence. The value of E0 decreases sharply with an increase in t from 1000 to ∼1800°C and after ∼2400°C it is practically independent of the degree of perfection of the graphite-like layers. The coefficient of coherence increases in density with an increase in t from 1000 to ∼2000°C and decreases as the result of appearance of disk-shaped cracks in a change in t from 2400 to 3200°C. The physical reasons for the rules found were analyzed.
Similar content being viewed by others
Literature cited
A. S. Kotosonov, I. Ya. Levintovich, and V. Ya. Kotosonova, “The interrelationship of Young's modulus and the macrostructure of polycrystalline graphites,” Probl. Prochn., No. 9, 81–84 (1985).
J. P. Watt, G. F. Davies, and R. J. O'Connel, “The elastic properties of composite materials,” Rev. Geophys. Space Phys.,14, No. 5, 541–563 (1976).
P. Christensen, An Introduction to the Mechanics of Composites [Russian translation], Mir, Moscow (1982).
A. S. Kotosonov, “Characteristics of the microstructure of artificial polycrystalline graphites based on electrical conductivity and magnetoresistance,” Dokl. Akad. Nauk SSSR,262, No. 1, 133–135 (1982).
I. Ya. Levintovich and A. S. Kotosonov, “The electrical resistance of layers of macroisotropic carbon materials with the structure of two-dimensional graphite,” Izv. Akad. Nauk SSSR, Neorgan. Mater.,25, No. 8, 1297–1302 (1989).
P. A. Thrower and W. N. Reynolds, “Microstructural changes in neutron-irradiated graphite,” J. Nucl. Mater.,8, No. 2, 221–226 (1963).
A. L. Sutton and V. C. Howard, “The role of porosity in the accommodation of thermal expansion in graphite,” ibid.,7, No. 1, 58–68 (1962).
D. B. Fishbach, “The kinetics and mechanism of graphitization,” in: The Chemistry and Physics of Carbon, Vol. 7, Dekker, New York (1971), pp. 1–105.
C. Baker and A. Kelly, “The effect of neutron irradiation on the elastic moduli of graphite single crystals,” Phil. Mag.,9, No. 102, 927–951 (1964).
P. R. Goggin and W. N. Reynods, “The elastic constants of reactor graphites,” ibid.,16, No. 140, 317–330 (1967).
J. B. Mason and R. H. Knibbs, “The Young's modulus of carbon and graphite artefacts,” Carbon,5, No. 5, 493–506 (1967).
R. E. Smith, G. B. Spence, J. E. Gubernatis, and J. A. Krumhansl, “Self-consistent calculations of elastic constants of polycrystalline graphite,” ibid.,14, No. 4, 185–189 (1986).
Author information
Authors and Affiliations
Additional information
Translated from Problemy Prochnosti, No. 1, pp. 69–73, January, 1990.
Rights and permissions
About this article
Cite this article
Levintovich, I.Y., Kotosonov, A.S. Structural factors determining the change in young's modulus of polycrystalline carbon materials in heat treatment. Strength Mater 22, 86–91 (1990). https://doi.org/10.1007/BF00774985
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00774985