Advertisement

Metallurgical and Materials Transactions A

, Volume 15, Issue 6, pp 1103–1110 | Cite as

Retarded grain boundary mobility in activated sintered molybdenum

  • P. E. Zovas
  • R. M. German
Symposium on Activated and Liquid Phase of Refractory Metals and Their Compounds

Abstract

Rapid grain growth accompanies the enhanced sintering of molybdenum treated with nickel additions. Grain growth is detrimental to sintering kinetics and mechanical properties. A sintering model is developed to illustrate that reducing grain boundary mobility is a means to increase the densification rate. A fine silica dispersion is added to molybdenum powder which is activated by the addition of nickel. This powder exhibits a long term sintering benefit due to retarded grain growth which is attributed to dispersoid drag effects on grain boundaries. These experimental powders are further analyzed through precision dilatometry, showing a characteristic shift in shrinkage rate during constant heating rate experiments. The shrinkage rate of molybdenum is increased by a factor of 10 at 1000°C when activated with 0.37 pct Ni. The shrinkage rate of nickel activated molybdenum is further increased by 67 pct with 1400 ppm silica dispersed at the interparticle grain boundaries.

Keywords

Metallurgical Transaction Shrinkage Rate Boundary Mobility Densification Rate Molybdenum Powder 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    H. Alexander and R.W. Balluffi:Acta Metall., 1957, vol. 5, pp. 666–77.CrossRefGoogle Scholar
  2. 2.
    P. J. Jorgensen:J. Amer. Ceram. Soc, 1965, vol. 48, pp. 207–10.CrossRefGoogle Scholar
  3. 3.
    J.E. Burke:J. Amer. Ceram. Soc, 1957, vol. 40, pp. 80–85.CrossRefGoogle Scholar
  4. 4.
    C.W. Corti and P. Cotterill:Powder Met. Inter., 1974, vol. 6, pp. 23–25.Google Scholar
  5. 5.
    C.O. McHugh, T.J. Whalen, and M. Humenik:J. Amer. Ceram. Soc, 1966, vol. 49, pp. 486–91.CrossRefGoogle Scholar
  6. 6.
    C. Agte:Hutnicke Listy, 1953, vol. 8, pp. 227–34.Google Scholar
  7. 7.
    V. V. Panichkina, V. V. Skorokhod, and A. F. Khrienko:Soviet Powder Met. Metal Ceram., 1967, vol. 6, pp. 558–60.CrossRefGoogle Scholar
  8. 8.
    G.A. Gospodinov, V. K. Pangarova, and D. K. Lambiev:Soviet Powder Met. Metal Ceram., 1976, vol. 15, pp. 159–61.CrossRefGoogle Scholar
  9. 9.
    V. V. Skorokhod, S. M. Solonin, L. L. Kolomiets, and L. I. Shnaider- man:Soviet Powder Met. Metal Ceram., 1976, vol. 15, pp. 435–38.CrossRefGoogle Scholar
  10. 10.
    R.M. German and Z. A. Munir:J. Less-Common Metals, 1978, vol. 58, pp. 61–74.CrossRefGoogle Scholar
  11. 11.
    M.M. Lejbrant and W. Rutkowski:Inter. J. Powder Met. Powder Tech., 1978, vol. 14, pp. 17–30.Google Scholar
  12. 12.
    Z.A. Munir and R.M. German ;High Temp. Sci., 1977, vol. 9, pp. 275–83.Google Scholar
  13. 13.
    W. A. Kaysser, M. Hoffmann, and G. Petzow:Proceedings PIM-82 (International Powder Metallurgy Conference, Florence, Italy, June 1982), Associazione Italiana di Metallurgia, Milano, 1982, pp. 17–22.Google Scholar
  14. 14.
    J.T. Smith:J. Appl. Phys., 1965, vol. 36, pp. 595–98.CrossRefGoogle Scholar
  15. 15.
    G.V. Samsonov and V.I. Yakovlev:Soviet Powder Met. Metal Ceram., 1970, vol. 9, pp. 30–36.CrossRefGoogle Scholar
  16. 16.
    I. Amato:Mater. Sci. Eng., 1972, vol. 10, pp. 15–22.CrossRefGoogle Scholar
  17. 17.
    Chaojin Li and R.M. German:Metall. Trans. A, 1983, vol. 14A, pp. 2031–41.CrossRefGoogle Scholar
  18. 18.
    R.M. German and Z. A. Munir:Reviews Powder Met. Physical Ceram., 1982, vol. 2, pp. 9–43.Google Scholar
  19. 19.
    T. Ikegami, M. Tsutsumi, S. Matsuda, S. Shirasaki, and H. Suzuki:J. Appl. Phys., 1978, vol. 48, pp. 4238–41.CrossRefGoogle Scholar
  20. 20.
    G.C. Kuzcynski:Powder Met., 1963, vol. 6, pp. 1–16.Google Scholar
  21. 21.
    R. J. Brook:J. Amer. Ceram. Soc, 1969, vol. 52, pp. 56–57.CrossRefGoogle Scholar
  22. 22.
    F.M.A. Carpay:J. Amer. Ceram. Soc, 1977, vol. 60, pp. 82–83.CrossRefGoogle Scholar
  23. 23.
    W. D. Kingery and B. Francois:J. Amer. Ceram. Soc, 1965, vol. 48, pp. 546–47.CrossRefGoogle Scholar
  24. 24.
    R. L. Coble:J. Appl. Phys., 1961, vol. 32, pp. 787–92.CrossRefGoogle Scholar
  25. 25.
    T. K. Gupta:Amer. Ceram. Soc, 1978, vol. 61, pp. 191–95.CrossRefGoogle Scholar
  26. 26.
    C.H. Hsueh, A.G. Evans, and R.L. Coble:Acta Metall., 1982, vol. 30, pp. 1269–79.CrossRefGoogle Scholar
  27. 27.
    R.M. German:Science Sintering, 1983, vol. 15, pp. 27–42.Google Scholar
  28. 28.
    R.M. German:Sintering — Theory and Practice, D. Kolar, S. Pejovnik, and M.M. Ristic, eds., Elsevier Scientific, Amsterdam, Netherlands, 1982, pp. 177–83.Google Scholar
  29. 29.
    P.E. Zovas, R. M. German, K.W. Hwang, and J. Li:J. Metals, 1983, vol. 35, no. 1, pp. 28–33.Google Scholar
  30. 30.
    R. M. German and A. Labombard:Inter. J. Powder Metal. Powder Tech., 1982, vol. 18, pp. 147–56.Google Scholar
  31. 31.
    W. A. Kaysser, M. Amtenbrink, and G. Petzow:Sintering — Theory and Practice, D. Kolar, S. Pejovnik, and M. M. Ristic, eds., Elsevier Scientific, Amsterdam, Netherlands, 1982, pp. 275–82.Google Scholar
  32. 32.
    M. F. Yan:Advances in Powder Technology, G. Y. Chin, ed., ASM, Metals Park, OH, 1982, pp. 99–133.Google Scholar
  33. 33.
    W. S. Young and I. B. Cutler:J. Amer. Ceram. Soc, 1970, vol. 53, pp. 659–63.CrossRefGoogle Scholar
  34. 34.
    R.M. German and V. Ham:Metall. Trans. A, 1979, vol. 10A, pp. 1593–96.CrossRefGoogle Scholar
  35. 35.
    Y. Masuda and R. Wantanbe:Sintering Processes, G. Kuczynski, ed., Plenum Press, New York, NY, 1980, pp. 3–21.CrossRefGoogle Scholar

Copyright information

© The Metallurgical of Society of AIME 1984

Authors and Affiliations

  • P. E. Zovas
    • 1
  • R. M. German
    • 2
  1. 1.Engineering Staff, Sikorsky AircraftStratford
  2. 2.Materials Engineering DepartmentRensselaer Polytechnic InstituteTroy

Personalised recommendations