Thermal Analysis and Production of As-Cast Al 7075/6060 Bilayer Billets

  • Thomas GreßEmail author
  • Tim Mittler
  • Simon Schmid
  • Hui Chen
  • Noomane Ben Khalifa
  • Wolfram Volk


Load-adjusted, weight-optimized components can be fabricated by following a multi-material approach. Integrating the respective advantages of strength and corrosion resistance of Al 7075 and Al 6060 into a single structural component leads to a complex property profile. Compound casting offers a high potential in terms of process chain shortening, material efficiency and bonding quality. The present paper focuses on the production of aluminum bilayer billets by multi-step, discontinuous compound casting. Process conditions influencing the formation of a cohesive bond at the interface are investigated. A fundamental thermal analysis is conducted in order to fully characterize the casting alloys. A process window for metallurgical bonding of Al 7075 and Al 6060 can be defined using a combined approach of process parameters and thermophysical data. The primary bonding mechanism is found to be the epitaxial solidification which occurs through remelting and recrystallization of the substrate alloy. Here the dendrite coherence point constitutes a critical level of the near-interface substrate temperature in terms of forming a solid solution. Epitaxy, phase composition and intermetallic diffusion processes are analyzed using SEM–EDS.


thermal analysis aluminum bimetal dendrite coherence point compound casting bilayer billet epitaxy 



The “Determination and control of bonding properties in aluminum composites in the combination of compound casting and forming” project is funded by the German Research Foundation (DFG) under grant VO-1487/25-1. The authors acknowledge the financial support from the DFG. Furthermore, the authors would like to express their gratitude to the Fraunhofer Research Institute for Casting, Composite and Processing Technology IGCV for their assistance in the measurement of thermophysical data.


  1. 1.
    W. Stets, Dissertation (Ruhr University Bochum, 1998)Google Scholar
  2. 2.
    C.J. Nerl, Dissertation (Technical University of Munich, 2014)Google Scholar
  3. 3.
    A. Ißleib, A. Friedel, I. Lubojanski, Gießerei-Praxis 23(24), 442–447 (1995)Google Scholar
  4. 4.
    D. Pan, K. Gao, J. Yu, Mater. Sci. Technol. 5, 934–939 (1989)CrossRefGoogle Scholar
  5. 5.
    P. Kazanowski, M.E. Epler, W.Z. Misiolek, Mater. Sci. Eng., A 369, 170–180 (2004)CrossRefGoogle Scholar
  6. 6.
    F. Riemelmoser, H. Kilian, P. Widlicki, W.W. Thedja, K. Müller, H. Garbacz, K.J. Kurzydlowski, in Strangpressen, ed By H. Gers (Wiley-VCH, Weinheim, 2007), pp. 248–257Google Scholar
  7. 7.
    K.J.M. Papis, B. Hallstedt, J.F. Löffler, P.J. Uggowitzer, Acta Mater. 56, 3036–3043 (2008)CrossRefGoogle Scholar
  8. 8.
    E. Hajjari, M. Divandari, S.H. Razavi, S.M. Emami, T. Homma, S. Kamado, J. Mater. Sci. 46, 6491–6499 (2011)CrossRefGoogle Scholar
  9. 9.
    C. Nerl, M. Wimmer, H. Hoffmann, E. Kaschnitz, F. Langbein, W. Volk, J. Mater. Process. Technol. 214, 1445–1455 (2014)CrossRefGoogle Scholar
  10. 10.
    T. Greß, T. Mittler, W. Volk, Mater. Sci. Technol. (2018). CrossRefGoogle Scholar
  11. 11.
    T. Mittler, T. Greß, M. Feistle, M. Krinninger, U. Hofmann, J. Riedle, R. Golle, W. Volk, J. Mater. Process. Technol. 263, 33–41 (2019)CrossRefGoogle Scholar
  12. 12.
    T. Haga, R. Nakamura, S. Kumai, H. Watari, Arch. Mater. Sci. Eng. 37, 117–124 (2009)Google Scholar
  13. 13.
    H. Liang, Z. Xue, C. Wu, Q. Liu, Y. Wu, Acta Metall. Sin. (Engl. Lett.) 23, 206–214 (2010)Google Scholar
  14. 14.
    Y.J. Su, X.H. Liu, H.Y. Huang, X.F. Liu, J.X. Xie, Metall. Mater. Trans. A 42A, 4088–4099 (2011)CrossRefGoogle Scholar
  15. 15.
    T. Liu, Q. Wang, Y. Sui, Q. Wang, W. Ding, Mater. Des. 68, 8–17 (2015)CrossRefGoogle Scholar
  16. 16.
    M. Pintore, O. Starykov, T. Mittler, W. Volk, B. Tonn, Int. J. Metalcasting 12, 79–88 (2017)CrossRefGoogle Scholar
  17. 17.
    E. Moosavi-Khoonsari, F. Jalilian, F. Paray, D. Emadi, R.A.L. Drew, Mater. Sci. Technol. 27, 1707–1717 (2011)CrossRefGoogle Scholar
  18. 18.
    L. Dong, W. Chen, L. Hou, Y. Liu, Q. Luo, J. Mater. Process. Technol. 238, 325–332 (2016)CrossRefGoogle Scholar
  19. 19.
    G. Schulz, Die Metallurgie des Schweißens, 4th edn. (Springer, Berlin, 2010), p. 302CrossRefGoogle Scholar
  20. 20.
    D. Herrmann, METALL 11, 541–544 (2010)Google Scholar
  21. 21.
    M.D. Anderson, K.T. Kubo, T.F. Bischoff, W.J. Fenton, E.W. Reeves, B. Spendlove, R.B. Wagstaff, US Patent US 2005/0011630 A1 (2005)Google Scholar
  22. 22.
    M. Wimmer, Dissertation (Technical University of Munich, 2015)Google Scholar
  23. 23.
    C. Nerl, M. Wimmer, S. Riedel, H. Hoffmann, in Stranggießen, ed By H.R. Müller (Werkstoff-Informationsgesellschaft, Frankfurt, 2010), pp. 93–98Google Scholar
  24. 24.
    S. Heugenhauser, Dissertation (Montanuniversität Leoben, 2018)Google Scholar
  25. 25.
    G.Y. Yan, F. Mao, F. Chen, W. Wu, Z.Q. Cao, T.M. Wang, T.J. Li, Trans. Nonferrous Met. Soc. China 26, 895–904 (2016)CrossRefGoogle Scholar
  26. 26.
    G.Y. Yan, F. Mao, Z.Q. Cao, T.J. Li, T.M. Wang, Trans. Nonferrous Met. Soc. China 28, 9–19 (2018)CrossRefGoogle Scholar
  27. 27.
    J.J. Valencia, P.N. Quested, ASM Handb. 15, 468–481 (2008)Google Scholar
  28. 28.
    P.T. Summers, Y. Chen, C.M. Rippe, B. Allen, A.P. Mouritz, S.W. Case, B.Y. Lattimer, Fire Sci. Rev. 4(3), 1–36 (2015)Google Scholar
  29. 29.
    S. Benum, D. Mortensen, H. Fjær, H.G. Øverlie, O. Reiso, Light Met. 3, 887–894 (1992)Google Scholar
  30. 30.
    A.K. Dahle, D.H. StJohn, Acta Mater. 47, 31–41 (1999)CrossRefGoogle Scholar
  31. 31.
    L. Bäckerud, E. Król, J. Tamminen, Solidification Characteristics of Aluminium Alloys, Volume 1: Wrought Alloys, 1st edn. (Skanaluminium, Oslo, 1986), pp. 143–147Google Scholar
  32. 32.
    A.H. Ahmad, S. Naher, D. Brabazon, Key Eng. Mater. 554–557, 582–595 (2013)CrossRefGoogle Scholar
  33. 33.
    S. Hiebler, Dissertation (Technical University of Munich, 2007)Google Scholar
  34. 34.
    K. Weiß, Dissertation (RWTH Aachen University, 1986)Google Scholar
  35. 35.
    N. Coniglio, C.E. Cross, Weld. World 50, 14–23 (2006)CrossRefGoogle Scholar

Copyright information

© American Foundry Society 2018

Authors and Affiliations

  1. 1.Technical University of Munich, Chair of Metal Forming and CastingGarchingGermany
  2. 2.Institute of Product and Process InnovationLeuphana University of LüneburgLüneburgGermany
  3. 3.Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Magnesium Innovation Centre MagICGeesthachtGermany

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