Metallurgical and Materials Transactions A

, Volume 29, Issue 11, pp 2835–2842 | Cite as

Role of cold work and SiC reinforcements on the β′/β precipitation in Al-10 pct Mg alloy

  • N. R. M. R. Bhargava
  • I. Samajdar
  • S. Ranganathan
  • M. K. Surappa
Article
Received:

Abstract

Elevated temperature (above 100 °C) precipitation behaviors were studied in A1-10 wt pct Mg alloy and the same alloy reinforced with SiC particles through electrical resistivity, hardness, differential scanning calorimetry (DSC), and microscopy. Two distinct hardness peaks/resistivity drops, as associated with two precipitation events, were identified: (1) α (solid solution) → β′ (metastable hex precipitate) → β (Al3Mg2, stable complex cubic precipitate); and (2) α → β. Equilibrium β precipitates, transformed from metastable β′, were observed to possess a wide variet of orientation relationships with the matrix and were often observed to be twinned. A more restricted orientation relationship (only three variants) between β and matrix was observed in direct decomposition of α to β, and β precipitates, within these orientation relationships, were never observed to be twinned. In a predominantly binary Al-Mg system, direct precipitation of β was observed to dominate. However, the presence of trace amounts of boron nitride and/or boron (or a large supply of matrix dislocations) either from cold work, or (as in case of composites) from the thermal mismatch between the SiC and Al matrix, produced both precipitation events with event 1 dominant.

Keywords

Differential Scanning Calorimetry Material Transaction Boron Nitride Orientation Relationship Heat Evolution 
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.
    Aluminum: Properties and Physical Metallurgy, J.E. Hatch, ed., ASM, Metals Park, OH, 1993.Google Scholar
  2. 2.
    L.F. Mondolfo: Aluminum Alloys: Structure and Properties, Butterworth, and Co., London, 1976, pp. 312–23.Google Scholar
  3. 3.
    A. Kelly and R.B. Nicholson: Progr. Mater. Sci., Pergamon Press, London, 1963, vol. 10, pp. 209–11.Google Scholar
  4. 4.
    S. Samson: Acta Cryst., 1965, vol. 19, p. 401.CrossRefGoogle Scholar
  5. 5.
    T. Sato and A. Kamio: Mater. Sci. Eng., 1991, vol. A146, pp. 161–80.Google Scholar
  6. 6.
    T. Sato, Y. Kojima, and T. Takashi: Metall. Trans. A, 1982, vol. 13A, pp. 1373–78.Google Scholar
  7. 7.
    K. Osamura and T. Ogura: Metall. Trans. A, 1984, vol. 15A, pp. 835–42.Google Scholar
  8. 8.
    M. Van Rooyen, J.A. Sinte Maarensdijk, and E.J. Mittemeijer: Metall. Trans. A, 1988, vol. 19A, pp. 2433–43.Google Scholar
  9. 9.
    S. Nebti, D. Hamana, and G. Cizeron: Acta Metall. Mater., 1995, vol. 43, pp. 3583–88.CrossRefGoogle Scholar
  10. 10.
    C. Panseri, T. Federighi, and S. Ceresara: Trans. AIME, 1963, vol. 227, pp. 1122–26.Google Scholar
  11. 11.
    Y. Kojima, T. Takahashi, M. Kubo, and T. Moringa: Metall. Trans. A, 1981, vol. 12A, pp. 1113–17.Google Scholar
  12. 12.
    W.A. Pollard: J. Inst. Met., 1964, vol. 93, p. 339.Google Scholar
  13. 13.
    T. Mukai, K. Higashi, and S. Tanimura: Mater. Sci. Eng., 1994, vol. A176, pp. 181–89.Google Scholar
  14. 14.
    N.R.M.R. Bhargava, I. Samajdar, S. Ranganathan, and M.K. Surappa: Indian Institute of Science, Bangalore, Ph.D Thesis, 1997.Google Scholar
  15. 15.
    S. Suresh and K.K. Chawla: in Fundamentals of MMCs, S. Suresh, A. Mortensen, and A. Needleman, eds., Butterworth-Heinemann, Boston, MA, 1993, pp. 119–36.Google Scholar
  16. 16.
    C. Badini, F. Marino, and E. Verne: Mater Sci. Eng., 1995, vol. A191, pp. 185–91.Google Scholar
  17. 17.
    H. Lee, W. Lu, and S.L. Chan: Scripta Metall. Mater., 1992, vol. 26, pp. 1723–26.CrossRefGoogle Scholar
  18. 18.
    M.J. Starink and P. Van Mourik: Metall. Trans. A, 1991, vol. 22A, pp. 665–74.Google Scholar
  19. 19.
    I. Dutta, C.P. Harper, and G. Dutta: Metall. Mater. Trans. A, 1994, vol. 25A, pp. 1591–1602.Google Scholar
  20. 20.
    B. Dutta and M.K. Surappa: Scripta Metall. Mater., 1995, vol. 32, p. 731.CrossRefGoogle Scholar
  21. 21.
    J.W. Martin and R.D. Doherty: Stability of Microstructures in Metallic Systems, Cambridge University Press, London, 1976.Google Scholar
  22. 22.
    D.A. Porter and K.E. Easterling: Phase Transformations in Metals And alloys, T.J. Press Ltd., Cornwell, United Kingdom, 1989.Google Scholar
  23. 23.
    H.R. Shercliff and M.F. Ashby: Acta Metall. Mater., 1990, vol. 38, pp. 1789–1802.CrossRefGoogle Scholar
  24. 24.
    G.C. Weatherly and R.B. Nicohlson: Phil. Mag., 1968, vol. 16, pp. 801–31.Google Scholar
  25. 25.
    M.F. Komarov et al.: Fiz. Met. Metalloved., 1966, vol. 21 (6), pp. 858–67.Google Scholar
  26. 26.
    L.I. Kaygorodova, N.N. Buynov, and M.F. Komarova: Fiz. Met. Metalloved., 1982, vol. 54 (3), pp. 542–47.Google Scholar
  27. 27.
    N.N. Buynov and L.I. Kaygorodova: Fiz. Met. Metalloved., 1985, vol. 59 (1), pp. 91–95.Google Scholar
  28. 28.
    J.W. Cahn and G. Kalonji: Solid State Phase Transformation, H.I. Aaronson, D.E. Laughlin, R.F. Sekerka, and C.M. Wayman, eds. AIME, Warrendale, PA, 1981, pp. 3–14.Google Scholar
  29. 29.
    N. Kuwano et al.: ICOMAT-86, Japan Institute of Metals, Sendai, 1987, pp. 355–58.Google Scholar
  30. 30.
    H.C. Montgomery: J. Appl. Phys., 1971, vol. 42, p. 2971.CrossRefGoogle Scholar

Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 1998

Authors and Affiliations

  • N. R. M. R. Bhargava
    • 1
  • I. Samajdar
    • 2
  • S. Ranganathan
    • 3
  • M. K. Surappa
    • 3
  1. 1.the Department of Metallurgical EngineeringAndhra UniversityVisakhapatnamIndia
  2. 2.the Department of Metallurgical Engineering and Materials ScienceIndian Institute of TechnologyMumbaiIndia
  3. 3.the Department of MetallurgyIndian Institute of ScienceBangaloreIndia

Personalised recommendations