Metallurgical and Materials Transactions A

, Volume 38, Issue 7, pp 1388–1394 | Cite as

The Influence of Fluid Flow on the Microstructure of Directionally Solidified AlSi-Base Alloys

SYMPOSIUM: Solidification Modeling and Microstructure Formation: In Honor of Prof. John Hunt

Abstract

To obtain a quantitative understanding of the effect of fluid flow on the microstructure of cast alloys, a technical Al-7 wt pct Si-0.6 wt pct Mg alloy (A357) has been directionally solidified with a medium temperature gradient under well-defined thermal and fluid-flow conditions. The solidification was studied in an aerogel-based furnace, which established flat isotherms and allowed the direct optical observation of the solidification process. A coil system around the sample induces a homogeneous rotating magnetic field (RMF) and, hence, a well-defined flow field close to the growing solid-liquid interface. The application of RMFs during directional solidification results in pronounced segregation effects: a change to pure eutectic solidification at the axis of the sample at high magnetic field strengths is observed. The investigations show that with increasing magnetic induction and, therefore, fluid flow, the primary dendrite spacing decreases, whereas the secondary dendrite arm spacing increases. An apparent flow effect on the eutectic spacing is observed.

References

  1. 1.
    M.E. Glicksman, M.B. Koss, L.T. Bushnell, J.C. LaCombe, and E.A. Winsa: Materials and Fluids under Low Gravity, Lecture Notes in Physics, L. Ratke, H. Walter, and B. Feuerbacher, eds., Springer Verlag, Heidelberg, 1996, pp. 63–75Google Scholar
  2. 2.
    S. Steinbach, L. Ratke, and H.D. Masslow: Proc. 17th Symp. on European Rocket and Balloon Programmes and Related Research, Sandefjord, Norway, ESA SP-590, 2005, pp. 521–26Google Scholar
  3. 3.
    W. Kurz, D.J. Fisher: Fundamentals of Solidification, Trans Tech Publications, Aedermannsdorf, Switzerland, 1989, pp. 1–316Google Scholar
  4. 4.
    C. Beckermann, H.-J. Diepers, I. Steinbach, A. Karma, X. Tong: J. Comp. Phys., 1999, vol. 154, pp. 468–96CrossRefGoogle Scholar
  5. 5.
    H.-J. Diepers, C. Beckermann, I. Steinbach: Acta Mater., 1999, vol. 47, pp. 3663–78CrossRefGoogle Scholar
  6. 6.
    K. Moenipur, K. Eigenfeld: Giessereiforschung, 2004, vol. 50, pp. 103–09Google Scholar
  7. 7.
    C. Beckermann: Int. Mater. Rev., 2002, vol. 47, pp. 243–61CrossRefGoogle Scholar
  8. 8.
    M.C. Flemings, G.E. Nereop: Trans. AIME, 1967, vol. 239, pp. 1449–61Google Scholar
  9. 9.
    P.A. Davidson, F. Boysan: Appl. Sci. Res., 1987, vol. 44, pp. 241–59CrossRefGoogle Scholar
  10. 10.
    M. Hainke, J. Friedrich, G. Müller: J. Mater. Sci., 2004, vol. 39, pp. 2011–15CrossRefGoogle Scholar
  11. 11.
    R. Trivedi, W. Kurz: Int. Mater. Rev., 1994, vol. 39, pp. 49–74Google Scholar
  12. 12.
    J. Alkemper, S. Sous, C. Stöcker, L. Ratke: J. Cryst. Growth, 1998, vol. 191, pp. 252–60CrossRefGoogle Scholar
  13. 13.
    S. Sous, L. Ratke: Z. Metallkd., 2005, vol. 96(4), pp. 362–69Google Scholar
  14. 14.
    J. Alkemper, L. Ratke, and S. Sous: Proc. 4th Decennial Conf. Solidification Processing, Sheffield, J. Beech and H. Jones, eds., Sheffield University, Sheffield, 1997, pp. 463–67Google Scholar
  15. 15.
    J. Fricke: J. Non-Crystal. Solids, 1992, vol. 145, pp. 1–258CrossRefGoogle Scholar
  16. 16.
    P.H. Tewari, A.J. Hunt, J.G. Lieber, and K. Lufftus: Aerogels, J. Fricke, ed., Springer Verlag, Berlin, 1985, p. 142Google Scholar
  17. 17.
    S. Steinbach, L. Ratke: Mater. Sci. Forum, 2006, vol. 508, pp. 491–96Google Scholar
  18. 18.
    M. Hainke: Ph.D. Thesis, Technical Faculty Erlangen-Nuremberg, Erlangen, Germany, 2004Google Scholar
  19. 19.
    J.T. Mason, J.D. Verhoeven, R. Trivedi: J. Cryst. Growth, 1982, vol. 59, pp. 516–24CrossRefGoogle Scholar
  20. 20.
    R. Grugel, W. Kurz: Metall. Trans. A, 1987, vol. 18A, pp. 1137–42Google Scholar
  21. 21.
    B. Toloui, A. Hellawell: Acta Metall., 1976, vol. 24, pp. 565–73CrossRefGoogle Scholar
  22. 22.
    N. Whisler, T.Z. Kattamis: J. Cryst. Growth, 1972, vol. 15, pp. 20–24CrossRefGoogle Scholar
  23. 23.
    D.H. Kirkwood: Mater. Sci. Eng., 1985, vol. 73, pp. L1–L4CrossRefGoogle Scholar
  24. 24.
    K.A. Jackson, J.D. Hunt: Trans. AIME, 1966, vol. 236, pp. 1129–42Google Scholar
  25. 25.
    P.A. Davidson: An Introduction to Magnetohydrodynamics, Cambridge University Press, Cambridge, United Kingdom, 2001, pp. 1–427Google Scholar
  26. 26.
    J.D. Hunt: Sci. Technol. Adv. Mater., 2001, vol. 2(1), pp. 147–55CrossRefGoogle Scholar
  27. 27.
    J.D. Hunt, S.Z. Lu: Metall. Mater. Trans. A, 1996, vol. A27, pp. 611–23CrossRefGoogle Scholar
  28. 28.
    S. Steinbach: Ph.D. Thesis, RWTH, Aachen, 2005Google Scholar
  29. 29.
    P. Lehmann, R. Moreau, D. Camel, R. Bolcato: J. Cryst. Growth, 1998, vol. 183, pp. 690–704CrossRefGoogle Scholar
  30. 30.
    M. Rappaz, W.J. Boettinger: Acta Mater., 1999, vol. 47(11), pp. 3205–19CrossRefGoogle Scholar
  31. 31.
    A.M. Mullis: J. Mater. Sci., 2003, vol. 38, pp. 2517–23CrossRefGoogle Scholar
  32. 32.
    L. Ratke, W.K. Thieringer: Acta Metall., 1985, vol. 33, pp. 1793–1802CrossRefGoogle Scholar
  33. 33.
    L. Ratke, P.W. Voorhees: Growth and Coarsening: Ostwald Ripening in Material Processing (Engineering Materials), Springer Verlag, Berlin, 2002, pp. 1–295Google Scholar
  34. 34.
    S. Steinbach, L. Ratke: Micrograv. Sci. Technol., 2005, vol. XVI-1, pp. 111–15CrossRefGoogle Scholar
  35. 35.
    W.R. Wilcox, L.L. Regel: Acta Astronautica, 1996, vol. 38(4–8), pp. 511–16CrossRefGoogle Scholar
  36. 36.
    J.E. Gruzleski, B. Closset: The Treatment of Liquid Aluminum Silicon Alloy, AFS, Inc., Des Plaines, IL, USA, 1990, ISBN 0874331218Google Scholar

Copyright information

© THE MINERALS, METALS & MATERIALS SOCIETY and ASM INTERNATIONAL 2007

Authors and Affiliations

  1. 1.Institut für Materialphysik im Weltraum, DLRKölnGermany

Personalised recommendations