Journal of Materials Science

, Volume 30, Issue 11, pp 2843–2848 | Cite as

Optimization of hot workability of an Al-Mg-Si alloy using processing maps

  • J. Sarkar
  • Y. V. R. K. Prasad
  • M. K. Surappa
Papers

Abstract

The hot workability of an Al-Mg-Si alloy has been studied by conducting constant strain-rate compression tests. The temperature range and strain-rate regime selected for the present study were 300–550 °C and 0.001–1 s−1, respectively. On the basis of true stress data, the strain-rate sensitivity values were calculated and used for establishing processing maps following the dynamic materials model. These maps delineate characteristic domains of different dissipative mechanisms. Two domains of dynamic recrystallization (DRX) have been identified which are associated with the peak efficiency of power dissipation (34%) and complete reconstitution of as-cast microstructure. As a result, optimum hot ductility is achieved in the DRX domains. The strain rates at which DRX domains occur are determined by the second-phase particles such as Mg2Si precipitates and intermetallic compounds. The alloy also exhibits microstructural instability in the form of localized plastic deformation in the temperature range 300–350 °C and at strain rate 1 s−1.

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References

  1. 1.
    H. J. McQueen, E. Evangelista and N. D. Ryan, in “Proceedings of Recrystallization 90”, edited by T. Chandra, (Metallurgical Society of AIME, Warrendale, PA, 1990) p. 89.Google Scholar
  2. 2.
    H. J. McQueen, in “Proceedings of Hot Deformation of Aluminium Alloys”, edited by Langdon et al. (Minerals, Metals and Materials Society, 1991) p. 31, 105.Google Scholar
  3. 3.
    H. Yamagata, Scripta Metall. Mater. 27 (1992) 201.Google Scholar
  4. 4.
    H. J. McQueen and N. Ryum, Scand. J. Met. 14 (1985) 183.Google Scholar
  5. 5.
    M. Raghavan and E. Shapiro, Metall. Trans. 11A (1980) 117.Google Scholar
  6. 6.
    M. A. Zaidi and T. Sheppard, Met. Sci. 16 (1982) 2229.Google Scholar
  7. 7.
    K. J. Gardener and R. Grimes, ibid. 3–4 (1979) 216.Google Scholar
  8. 8.
    T. Sheppard, N. C. Parsons and M. A. Zaidi, ibid. 17 (1983) 481.Google Scholar
  9. 9.
    H. J. McQueen, E. Evangelista and M. E. Kassner, Z. Metallkde 82 (1991) 336.Google Scholar
  10. 10.
    F. R. Castro-Fernandez and C. M. Sellars, Mater. Sci. 4 (1988) 621.Google Scholar
  11. 11.
    A. Espedal, H. Gjestland and N. Ryum, Scand. J. Met. 18 (1989) 131.Google Scholar
  12. 12.
    E. Evangelista, A. Forcellese, F. Gabrielli and P. Mengucci, in “Proceedings of Hot Deformation of Aluminium Alloys”, edited by Langdon et al, (Minerals, Metals and Materials Society, 1991) p. 121.Google Scholar
  13. 13.
    Y. V. R. K. Prasad, H. L. Gegel, S. M. Doraivelu, J. C. Malas, J. T. Morgan, K. A. Lark and D. A. Barker, Metall. Trans. 15A (1984) 1883.Google Scholar
  14. 14.
    J. M. Alexander, “Modeling Hot Deformation of Steels: An Approach to Understanding and Behaviour” (Springer-Verlag, Berlin, 1989).Google Scholar
  15. 15.
    H. L. Gegel, “Experimental Verification of Process Models” (ASM, Metals Park, OH, 1983).Google Scholar
  16. 16.
    A. K. S. Kalyan Kumar, MS Thesis, Indian Institute of Science, Bangalore, India (1987).Google Scholar
  17. 17.
    Y. V. R. K. Prasad and N. Ravichandran, Bull. Mater. Sci. 14 (1991) 1241.Google Scholar
  18. 18.
    R. Raj, Metall. Trans. 12A (1981) 1089.Google Scholar
  19. 19.
    L. F. Mondolfo, “Aluminium Alloys: Structure and Properties” (Butterworths, London, 1976).Google Scholar

Copyright information

© Chapman & Hall 1995

Authors and Affiliations

  • J. Sarkar
    • 1
  • Y. V. R. K. Prasad
    • 1
  • M. K. Surappa
    • 1
  1. 1.Centre for Advanced Study, Department of MetallurgyIndian Institute of ScienceBangaloreIndia

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