Metallurgical Transactions

, Volume 5, Issue 11, pp 2365–2373 | Cite as

Density changes accompanying the annealing of wrought thoriated tungsten wire

  • T. E. Dunham
  • R. F. Hehemann
Transformations
Received:

Abstract

Density measurements were made on 0.762 mm W-l wt pct ThO2 wires which had been annealed at temperatures between 1000°C and 2000°C for times up to 120 min. Selected specimens were examined using optical and scanning electron microscopy. The results of this study indicate that the low, as-worked wire density is a result of large cracks associated with the ThO2 particles. Time-temperature annealing regimes, significantly below those necessary for recrystallization of the wire, result in partial healing of the cracks. This crack healing process can be followed qualitatively by observing longitudinal fracture surfaces in the scanning electron microscope and quantitatively by changes in the density of the wire. The apparent activation energy for the crack healing process was found to be 57.8 kcal/mole. The results suggest that crack closure is a result of both shear and grain boundary diffusion transport processes. It is concluded that the presence of cracks can influence the morphology of the recrystallized grains.

Keywords

Apparent Activation Energy Crack Closure Crack Size Tungsten Wire ThO2 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    L. M. Clareborough, M. E. Hargreaves, and G. W. West:Proc. Roy. Soc, 1955, A232, p. 252.Google Scholar
  2. 2.
    L. M. Clareborough, M. E. Hargreaves, and G. W. West:Phil. Mag., 1956, vol. 1, no. 8, p. 528.Google Scholar
  3. 3.
    A. N. Stroh:Phil. Mag., 1957, vol. 2, no. 8, p. 1.Google Scholar
  4. 4.
    F. Garfalo, Y. T. Chou, and V. Ambegarokar:Acta Met., 1960, vol. 8, p. 504.CrossRefGoogle Scholar
  5. 5.
    H. H. Podgurski:Trans. TMS-AIME, 1961, vol. 221, p. 389.Google Scholar
  6. 6.
    F. Garfalo and H. A. Wriedt:Acta Met., 1962, vol. 10, p. 1007.CrossRefGoogle Scholar
  7. 7.
    A. Gittins:Acta Met, 1968, vol. 16, p. 517.CrossRefGoogle Scholar
  8. 8.
    W. B. Beere and G. W. Greenwood:Met. Sci. J., 1971, vol. 5, p. 107.CrossRefGoogle Scholar
  9. 9.
    D. Hull and D. E. Rimmer:Phil. Mag., 1959, vol. 4, p. 673.Google Scholar
  10. 10.
    H.A. Wriedt and H.A. Hughes:Met. Trans., 1970, vol. 1, p. 3457.Google Scholar
  11. 11.
    V. N. Gridnew, V. G. Gavrilyuk, and Vu, Ya. Meshkov:Met. Sci. and Heat Treat, 1971, vol. 13, p. 20.CrossRefGoogle Scholar
  12. 12.
    A. Gittins:Nature, 1967, vol. 214, p. 586.CrossRefGoogle Scholar
  13. 13.
    C. J. Smithells:Tungsten, New York Chemical Publishing Company, 1953.Google Scholar
  14. 14.
    T. E. Dunham:Met. Trans., 1971, vol. 2, p. 2797.Google Scholar
  15. 15.
    T. E. Dunham and R. L. Daga:Met. Trans., 1973, vol. 4, p. 175.Google Scholar
  16. 16.
    C. J. Smithells:Metals Reference Book, Vol. II, Washington, Butterworths, 1962.Google Scholar
  17. 17.
    J. L. Walter and A. U. Seybolt:Trans. TMS-AIME, 1969, vol. 245, p. 1093.Google Scholar
  18. 18.
    G.D. Rieck:Acta Met., 1961, vol. 9, p. 825.CrossRefGoogle Scholar
  19. 19.
    M. F. Ashby:Phil. Mag., 1966, vol. 14, p. 1157.Google Scholar
  20. 20.
    S. Weissmann, B. S. Lement, and M. Cohen:TMS-AIME Proceedings, 1962, vol. 17, p. 137.Google Scholar
  21. 21.
    R. C. Koo:J. Less-Common Metals, 1961, vol. 3, p. 412.CrossRefGoogle Scholar
  22. 22.
    R. L. Andelin, J. D. Knight, and M. Kahn:Trans. TMS-AIME, 1965, vol. 233 p. 19.Google Scholar
  23. 23.
    R. E. Powel and T. S. Lundy:Acta Met., 1969, vol. 17, p. 979.CrossRefGoogle Scholar
  24. 24.
    K. G. Krieder and G. Bruggeman:Trans. TMS-AIME, 1967, vol. 239, p. 1222.Google Scholar
  25. 25.
    J. P. Barbour:Phys. Rev., 1960, vol. 117, p. 1452.CrossRefGoogle Scholar
  26. 26.
    N. C. Kothari:J. Less-Common Metals, 1963, vol. 5, p. 140.CrossRefGoogle Scholar
  27. 27.
    T. Vasilos and J. T. Smith:J. Appl. Phys., 1964, vol. 35, p. 215.CrossRefGoogle Scholar
  28. 28.
    T. Yao and Y. Anekoji:J. of Jap. Soc. of Powder Met., 1963, vol. 9, p. 163.Google Scholar
  29. 29.
    J. Langmuir:J. Franklin Inst., 1934, vol. 217, p. 543.CrossRefGoogle Scholar
  30. 30.
    E. von Pink and H. P. von Zingsheim:Planseeberichte fur Pulvermetallurgie, 1968, vol. 16, p. 277.Google Scholar

Copyright information

© American Society for Metals, The Melallurgical Society of AIME 1974

Authors and Affiliations

  • T. E. Dunham
    • 1
  • R. F. Hehemann
    • 2
  1. 1.Chemical Products PlantGeneral Electric CompanyCleveland
  2. 2.Department of MetallurgyCase Western Reserve UniversityCleveland

Personalised recommendations