Russian Journal of Non-Ferrous Metals

, Volume 58, Issue 6, pp 639–643 | Cite as

Structural Features of Al–Hf–Sc Master Alloys

  • E. A. Popova
  • P. V. Kotenkov
  • A. B. Shubin
  • E. A. Pastukhov
Physical Metallurgy and Heat Treatment


Microstructural features of new master alloys of the Al–Hf–Sc system with metastable aluminides with a cubic lattice identical to the lattice of a matrix of aluminum alloys are investigated using optical microscopy, scanning electron microscopy, and electron probe microanalysis. Binary and ternary alloys are smelted in a coal resistance furnace in graphite crucibles in argon. Alloys Al–0.96 at % Hf (5.98 wt % Hf) and Al–0.59 at % Hf (3.77 wt % Hf) are prepared with overheating above the liquidus temperature of about 200 and 400 K, respectively. Alloys are poured into a bronze mold, the crystallization rate in which is ~103 K/s. Metastable Al3Hf aluminides with a cubic lattice are formed only in the alloy overheated above the liquidus temperature by 400 K. Overheating of ternary alloys, in which metastable aluminides Al n (Hf1–xSc x ) formed, is 240, 270, and 370 K. Depending on the Hf-to-Sc ratio in the alloy, the fraction of hafnium in aluminides Al n (Hf1–xSc x ) varies from 0.46 to 0.71. Master alloys (at %) Al–0.26Hf–0.29Sc and Al–0.11Hf–0.25Sc (wt %: Al–1.70Hf–0.47Sc and Al–0.75Hf–0.42Sc) have a fine grain structure and metastable aluminides of compositions Al n (Hf0.58Sc0.42) and Al n (Hf0.46Sc0.54), respectively. Sizes of aluminides do not exceed 12 and 7 μm. Their lattice mismatch with a matrix of aluminum alloys is smaller than that for Al3Sc. This makes it possible to assume that experimental Al–Hf–Sc master alloys manifest a high modifying effect with their further use. In addition, the substitution of high-cost scandium with hafnium in master alloys can considerably reduce the consumption of the latter.


Al–Hf–Sc system alloys metastable aluminides cubic lattice supersaturated solid solutions 


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  1. 1.
    Hyde, K.B., Norman, A.F., and Prangnell, P.B., The effect of Ti on grain refinement in Al–Sc alloys, Mater. Sci. Forum, 2002, vols. 396–402, pp. 39–44.CrossRefGoogle Scholar
  2. 2.
    Min, Song., Yuehui, He., and Shanfeng, Fang., Effect of Zr content on the yield strength of an Al–Sc alloys, J. Mater. Eng. Perform, 2011, vol. 20, no. 3, p. 377.CrossRefGoogle Scholar
  3. 3.
    Dalen, M.E., Dunand, D.C., and Seidman, D.N., Effects of Ti additions on the nanostructure and creep properties of precipitation-strengthened Al–Sc alloys, Acta Mater., 2005, vol. 53, no. 15, p. 4225.CrossRefGoogle Scholar
  4. 4.
    Royset, J. and Ryum, N., Scandium in aluminium alloys, Int. Mater. Rev., 2005, vol. 50, no. 1, p. 19.CrossRefGoogle Scholar
  5. 5.
    Zakharov, V.V., Combined alloying of aluminum alloys with scandium and zirconium, Metal. Sci. Heat Treat., 2014, vol. 56, no. 5, pp. 281–286.CrossRefGoogle Scholar
  6. 6.
    Zakharov, V.V., Revisiting alloying aluminum alloys with transition metals, Metalloved. Term. Obrab., 2017, no. 2 (740), pp. 3–8.Google Scholar
  7. 7.
    Norman, A.F., Prangnell, P.B., and McEwen, R.S., The solidification behavior of dilute aluminium–scandium alloys, Acta Mater., 1998, vol. 46, no. 16, p. 5715.CrossRefGoogle Scholar
  8. 8.
    Marquis, E.A. and Seidman, D.N., Nanoscale structural evolution of Al3Sc precipitates in Al(Sc) alloys, Acta Mater., 2001, vol. 49, pp. 1909–1919.CrossRefGoogle Scholar
  9. 9.
    Fuller, C.B., Murray, J.L., and Seidman, D.N., Temporal evolution of the nanostructure of Al(Sc,Zr) alloys: Part I. Chemical compositions of Al3(Sc1–xZrx) precipitates, Acta Mater., 2005, vol. 53, no. 20, pp. 5401–5413.CrossRefGoogle Scholar
  10. 10.
    Knipling, K.E., Karnesky, R.A., Lee, C.P., Dunand, D.C., and Seidman, D.N., Precipitation evolution in Al–0.1Sc, Al–0.1Zr and Al–0.1Sc–0.1Zr (at %) alloys during isochronal aging, Acta Mater., 2010, vol. 58, pp. 5184–5195.CrossRefGoogle Scholar
  11. 11.
    Carlsson, A.E. and Meschter, P.J., Relative stability of L12, D022, and D023 structures in MAl3 compounds, J. Mater. Res., 1989, vol. 4, no. 5, pp. 1060–1063.CrossRefGoogle Scholar
  12. 12.
    Ghosh, G. and Asta, M., First-principles calculation of structural energetics of Al–TM (TM = Ti, Zr, Hf) intermetallics, Acta Mater., 2005, vol. 53, p. 3225.CrossRefGoogle Scholar
  13. 13.
    Harada, Y. and Dunand, D.C., Microstructure of Al3Sc with ternary transition-metal additions, Mater. Sci. Eng. A, 2002, vol. 329–331, pp. 686–695.CrossRefGoogle Scholar
  14. 14.
    Brodova, I.G., Zamyatin, V.M., Popel, P.S., Esin, V.O., Baum, B.A., Moiseev, A.I., Korshunov, I.P., and Polents, I.V., Formation conditions of metastable phases during the crystallization of Al–Zr alloys, Rasplavy, 1988, vol. 2, no. 6, pp. 23–27.Google Scholar
  15. 15.
    Brodova, I.G., Polents, I.V., Esin, V.O., and Lobov, B.M., Formation regularities of the cast structure of supercooled Al–Ti alloys, Fiz. Met. Metalloved., 1992, no. 1, pp. 84–89.Google Scholar
  16. 16.
    Norman, A.F. and Tsakiropoulos, P., Rapid solidification of Al–Hf alloys–solidification, microstructures and decomposition of solid-solutions, Int. J. Rapid Solid., 1991, vol. 6, no. 3.Google Scholar
  17. 17.
    Malek, P., Janecek, M., Smola, B., Bartuska, P., and Plestil, J., Structure and properties of rapidly solidified Al–Zr–Ti alloys, J. Mater. Sci., 2000, vol. 35, pp. 2625–2633.CrossRefGoogle Scholar
  18. 18.
    Popova, E.A., Shubin, A.B., Kotenkov, P.V., Pastukhov, E.A., Bodrova, L.E., and Fedorova, O.M., Al–Ti–Zr master alloys: structure formation, Rus. Metall. (Metally), vol. 2012, no. 5, pp. 357–361.Google Scholar
  19. 19.
    Popova, E.A., Kotenkov, P.V., Pastukhov, E.A., and Shubin, A.B., Master alloys Al–Sc–Zr, Al–Sc–Ti, and Al–Ti–Zr: their manufacture, composition, and structure, Rus. Metall. (Metally), vol. 2013, no. 8, pp. 590–594.Google Scholar
  20. 20.
    Popova, E.A., Kotenkov, P.V., and Pastukhov, E.A., Synergetic effect in modifying with master alloys having an aluminide cubic structure, Rus. Metall. (Metally), vol. 2016, no. 2, pp. 189–193.Google Scholar
  21. 21.
    Kotenkov, P.V., Popova, E.A., and Pastukhov, E.A., Evaluation of modifying ability of Al–Sc–Zr, Al–Sc–Ti, Al–Ti–Zr master alloys, Rasplavy, 2014, no. 4, pp. 21–27.Google Scholar
  22. 22.
    Murray, J.L., McAlister, A.J., and Kahan, D.J., The Al–Hf (aluminum–hafnium) system, J. Phase Equil., 1998, vol. 19, no. 4, pp. 376–379.CrossRefGoogle Scholar
  23. 23.
    Murray, J.L., The Al–Sc (aluminum–scandium) system, J. Phase Equil., 1998, vol. 19, no. 4, pp. 380–384.CrossRefGoogle Scholar
  24. 24.
    Kerr, H.W., Cisse, J., and Boiling, G.F., On equilibrium and nonequilibrium peritectic transformation, Acta Metall., 1974, vol. 22, pp. 77–686.CrossRefGoogle Scholar

Copyright information

© Allerton Press, Inc. 2017

Authors and Affiliations

  • E. A. Popova
    • 1
  • P. V. Kotenkov
    • 1
    • 2
  • A. B. Shubin
    • 1
  • E. A. Pastukhov
    • 1
  1. 1.Institute of Metallurgy, Ural BranchRussian Academy of SciencesYekaterinburgRussia
  2. 2.Ural Federal UniversityYekaterinburgRussia

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