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Journal of Materials Science

, Volume 29, Issue 9, pp 2436–2444 | Cite as

Synthesis of amorphous and metastable Ti40Al60 alloys by mechanical alloying of elemental powders

  • W. Guo
  • A. Iasonna
  • M. Magini
  • S. Martelli
  • F. Padella
Papers

Abstract

Ti40Al60 amorphous and metastable alloys have been prepared by mechanical alloying (MA), under controlled milling conditions in a planetary mill. Three different quantities of kinetic energy at the collision instant have been achieved by using balls of different size, φb = 5, 8 and 12 mm, keeping constant all other device parameters. Assuming the collision between the balls and the vial walls to be inelastic, during the early stage of alloying, the amount of energy transferred to the trapped powder could be estimated. The experimental results show that the milling with balls of diameter φb = 5 or 8 mm leads to a solid-state amorphization of the Ti40Al60 mixture, through the attainment of a supersaturated solid solution of aluminium into α-titanium. Otherwise, the milling causes the nucleation of the A1-fcc disordered form of the TiAl intermetallic compound. The end products of MA-induced solid-state reaction (SSR) have been ascribed to the different temperature reached by the powder during each collision and to the reaction time scale for the formation of the amorphous phase, δta, and for the nucleation of the non-equilibrium intermetallic compound, δtd. Differential scanning calorimetry has indicated that the crystallization of amorphous samples follows a two-step reaction. At a temperature Tc≈400 °C, the amorphous phase crystallizes into the A1 -fcc. TiAl phase having a measured heat of crystallization of 6.2 kJ(g at)−1. Upon further heating, the system undergoes A1 → L1o reordering transition with an enthalpy release of about 3.2 kJ (g at)−1.

Keywords

Differential Scanning Calorimetry Milling Intermetallic Compound Amorphous Phase Mechanical Alloy 
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.

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References

  1. 1.
    C. Suryanarayana, F. H. Froes and R. G. Rowe, Int. Mater. Rev. 36 (1991) 85.CrossRefGoogle Scholar
  2. 2.
    D. Vujic, Z. Li and S. H. Whang, Metall. Trans. 19A (1988) 2445.CrossRefGoogle Scholar
  3. 3.
    C. C. Koch, Mater. Sci. Technol. 15 (1991) 194.Google Scholar
  4. 4.
    W. Guo, S. Martelli, N. Burgio, M. Magini, F. Padella, E. Paradiso and I. Soletta, J. Mater. Sci. 26 (1990) 6190.CrossRefGoogle Scholar
  5. 5.
    L. Schultz, Mater. Sci. Eng. 97 (1988) 15.CrossRefGoogle Scholar
  6. 6.
    G. Cocco, I. Soletta, L. Battezzati, M. Barricco and S. Enzo, Philos. Mag. B61 (1990) 473.CrossRefGoogle Scholar
  7. 7.
    N. Burgio, A. Iasonna, M. Magini, S. Martelli and F. Padella, Nuovo Cimento 13D (1991) 459.CrossRefGoogle Scholar
  8. 8.
    F. Padella, E. Paradiso, N. Burgio, M. Magini, S. Martelli, W. Guo and A. Iasonna, J. Less-Common Metals 175 (1991) 79.CrossRefGoogle Scholar
  9. 9.
    W. Guo, S. Martelli, F. Padella, M. Magini, N. Burgio, E. Paradiso and U. Franzoni, Mater. Sci. Forum 88–90 (1991) 139.Google Scholar
  10. 10.
    U. Mizutani and C. H. Lee, J. Mater. Sci. 25 (1990) 399.CrossRefGoogle Scholar
  11. 11.
    A. Calka, Appl. Phys. Lett. 59 (1991) 1568.CrossRefGoogle Scholar
  12. 12.
    D. W. Marquart, J. Soc. Ind. Appl. Math. 91 (1963) 431.CrossRefGoogle Scholar
  13. 13.
    A. Guinier, “Théorie et Technique de la Radiocristallographie” (Dunod, Paris, 1964).Google Scholar
  14. 14.
    T. B. Massalsky, “Binary Phase Diagrams” (ASM, 1986).Google Scholar
  15. 15.
    “Phase Diagrams of Titanium Alloys” S. G. Glazunov (ed.), Israel Program for Scientific Translation (1965).Google Scholar
  16. 16.
    W. B. Pearson, “Handbook of Lattice Spacings and structure of Metals” (Pergamon Press, Oxford, 1967).Google Scholar
  17. 17.
    T. Tanamura, T. Sugai and M. Tanino, J. Mater. Sci. 25 (1990) 27.Google Scholar
  18. 18.
    H. Barker and L. M. Di, Mater. Sci. Forum 88–90 (1992) 27.Google Scholar
  19. 19.
    J. Eckert, L. Schultz and K. Urban, J. Non-Cryst Solids 130 (1991) 273.CrossRefGoogle Scholar
  20. 20.
    M. Magini, Mater. Sci. Forum 88–90 (1992) 121.CrossRefGoogle Scholar
  21. 21.
    D. R. Maurice and T. H. Courtney, Metall. Trans. 21A (1990) 289.CrossRefGoogle Scholar
  22. 22.
    S. P. Timoshenko and J. N. Goodier, “Theory of Elasticity” (McGraw-Hill, New York, 1970).Google Scholar
  23. 23.
    A. R. Yavary and P. J. Desré, Phys. Rev. Lett. 65 (1990) 2571.CrossRefGoogle Scholar
  24. 24.
    G. Mazzone, A. Montone and M. Vittori-Antisari, ibid. 65 (1990) 2019.CrossRefGoogle Scholar
  25. 25.
    U. Gösele and K. N. Tu, J. Appl. Phys. 66 (1989) 2619.CrossRefGoogle Scholar
  26. 26.
    “Handbook of Chemistry & Physics”, 47th Edn (1966–1967)Google Scholar
  27. 27.
    L. Guttman, Solid State Phys. 3 (1956) 1.CrossRefGoogle Scholar
  28. 28.
    M. Asta, D. De Fontaine, M. Van Schilfgaarde, M. Sluiter and M. Methfessel, Phys. Rev. B46 (1992) 5055.CrossRefGoogle Scholar

Copyright information

© Chapman & Hall 1994

Authors and Affiliations

  • W. Guo
    • 1
  • A. Iasonna
    • 1
  • M. Magini
    • 1
  • S. Martelli
    • 1
  • F. Padella
    • 1
  1. 1.Casaccia Dept. INN-NUMAAmorphous Materials Project, E.N.E.A.RomeItaly

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