Skip to main content
SpringerLink
Log in

Massive transformation and the formation of the ferromagnetic L10 phase in manganese-aluminum-based alloys

  • Published:
Metallurgical and Materials Transactions A Aims and scope Submit manuscript

Abstract

Manganese-aluminum alloys in the vicinity of the equiatomic composition exhibit an attractive combination of magnetic properties for technological applications, including bulk permanent magnets and thin-film devices. The technical magnetic properties derive from the formation of a metastable L10 intermetallic phase (τ-MnAl) characterized by a high, uniaxial magnetocrystalline anisotropy with an “easy” c-axis. Carbon is generally added to stabilize the tetragonal τ phase with respect to the stable phases in the system. The magnetic hysteresis behavior of the Mn-Al-C genre of permanent magnet alloys is extremely sensitive to the microstructure and defect structure produced during the formation of the τ phase (L10) within the high-temperature ε phase (hcp). In this study, modern metallographic techniques, including high-resolution electron microscopy (HREM), have been applied to elucidate the nature of the phase transformation and the evolution of the unique microstructure and defect structure characterizing the structural state of the ferromagnetic τ phase. It is concluded that the metastable τ phase is the product of a compositionally invariant, diffusional nucleation and growth process or massive transformation. The massive product nucleates preferentially at the grain boundaries of the parent ε phase and is propagated by the migration of incoherent interphase interfaces. The interphase interfaces are revealed to be faceted on various length scales. It is concluded that this faceting is not a feature of the bicrystallography of the parent and product phases. The high density of lattice defects within the τ phase, generated by the phase transformation, is attributed to growth faults produced during atomic attachment at the migrating interfaces. Classical nucleation theory has been applied quantitatively to the grain-boundary nucleation process and was found to be consistent with the observed time-temperature-transformation (TTT) behavior. Analysis of the growth kinetics gives an ΔH D value of 154 kJ mol−1 for the activation energy of the transboundary diffusional process controlling boundary migration.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. T.B. Massalski: Acta Metall., 1958, vol. 6, p. 243.

    Article  CAS  Google Scholar 

  2. S.K. Bhattacharyya, J.H. Perepezko, and T.B. Massalski: Acta Metall., 1974, vol. 22, p. 879.

    Article  CAS  Google Scholar 

  3. T.B. Massalski: Phase Transformations, ASM, Metals Park, OH, 1970, p. 433.

    Google Scholar 

  4. K.Z. Fung, A.V. Virkar, and D.L. Drobeck: J. Am. Ceram. Soc., 1994, vol. 77, p. 1638.

    Article  CAS  Google Scholar 

  5. P. Su and A.V. Virkar: J. Am. Ceram. Soc., 1996, vol. 79, p. 371.

    Article  CAS  Google Scholar 

  6. P. Wang, G.B. Viswanathan, and V.K. Vasudevan: Metall. Trans. A, 1992, vol. 23A, pp. 690–97.

    CAS  Google Scholar 

  7. S.A. Jones and M.J. Kaufman: Acta Mater., 1993, vol. 41, p. 387.

    Article  CAS  Google Scholar 

  8. X.D. Zhang, J.M.K. Wiezorek, M.J. Kaufman, M.H. Loretto, and H.L. Fraser: Phil. Mag. Lett., 1999, vol. 79, p. 519.

    Article  CAS  Google Scholar 

  9. J.M. Howe: Interfaces in Materials: Atomic Structure, Thermodynamics and Kinetics of Solid-Vapor, Solid-Liquid and Solid-Solid Interfaces, Wiley, New York, NY, 1997.

    Google Scholar 

  10. J.M. Howe: Mater. Trans., JIM, 1998, vol. 39, p. 3.

    CAS  Google Scholar 

  11. J.M. Howe, H.I. Aaaronson, and J.P. Hirth: Acta. Mater., 2000, vol. 48, p. 3977.

    Article  CAS  Google Scholar 

  12. M. Hillert: Metall. Trans. A, 1984, vol. 15A, pp. 411–19.

    CAS  Google Scholar 

  13. M.R. Plichta, J.M. Rigsbee, M.G. Hall, K.C. Russell, and H.I. Aaronson: Scripta Metall., 1976, vol. 10, p. 1065.

    Article  CAS  Google Scholar 

  14. M.R. Plichta and H.I. Aaronson: Acta Metall., 1980, vol. 28, p. 1041.

    Article  CAS  Google Scholar 

  15. T.B. Massalski: Mater. Sci. Eng., 1976, vol. 25, p. 119.

    Article  CAS  Google Scholar 

  16. J.H. Perepezko and T.D. Massalski: J. Mater. Sci., 1974, vol. 9, p. 899.

    Article  CAS  Google Scholar 

  17. D. Veeraraghavan, P. Wang, and V.K. Vasudevan: Acta Mater., 1999, vol. 47, p. 3313.

    Article  CAS  Google Scholar 

  18. X.D. Zhang, S. Godfrey, M. Weaver, M. Strangwood, P. Threadgill, M.J. Kaufman, and M.H. Loretto: Acta Mater., 1996, vol. 44, p. 3723.

    Article  CAS  Google Scholar 

  19. D.P. Hoydick, E.J. Palmiere, and W.A. Soffa: Scripta Mater., 1997, vol. 36, p. 151.

    Article  CAS  Google Scholar 

  20. D.P. Hoydick, E. Palmiere, and W.A. Soffa: J. Appl. Phys., 1997, vol. 81, p. 5624.

    Article  CAS  Google Scholar 

  21. M.L. Leadbeater, S.J. Allen, F. DeRosa, J.P. Harbison, T. Sands, R. Ramesh, L.T. Florez, and V.G. Keramidas: J. Appl. Phys., 1991, vol. 69, p. 4689.

    Article  CAS  Google Scholar 

  22. T. Sands, J.P. Harbison, M.L. Leadbeater, S.J. Allen, G.W. Hull, R. Ramesh, and V.G. Keramidas: Appl. Phys. Lett., 1990, vol. 57, p. 2609.

    Article  CAS  Google Scholar 

  23. N.I. Vlasova, G.S. Kandurova, Y.S. Shur, and N.N. Bykhanova: Phys. Met. Metall., 1981, vol. 51, p. 1.

    Google Scholar 

  24. P.L. Rossister and M.E. Houghton: Met. Forum, 1984, vol. 7, p. 187.

    Google Scholar 

  25. W.H. Dreizler and A. Menth: IEEE Trans. Mag., 1980, vol. Mag 16, p. 534.

  26. T.B. Massalski: Binary Alloy Phase Diagrams, TMS, Materials Park, OH, 1990.

    Google Scholar 

  27. J.J. Van Den Broek, H. Donkersloot, G. Van Tendeloo, and J. Van Landuyt: Acta Metall., 1979, vol. 27, p. 1497.

    Article  Google Scholar 

  28. A.V. Dobromyslov, A.E. Ermakov, N.I. Taluts, and M.A. Uimin: Phys. Status Solidi (a), 1985, vol. 88, p. 443.

    Article  CAS  Google Scholar 

  29. Y.J. Kim and J.H. Perepezko: Mater. Sci. Eng., 1993, vol. A163, p. 127.

    CAS  Google Scholar 

  30. V.M. Gundyrev, M.A. Uimin, A.E. Ermakov, and O.B. Andrreva: Phys. Status Solidi (a), 1985, vol. 91, p. K55.

  31. C. Müller, H.H. Stadelmaier, B. Reinsch, and G. Petzow: Z. Metallkd., 1996, vol. 87, p. 594.

    Google Scholar 

  32. W. Köster and E. Wachtel: Z. Metallkd., 1960, vol. 51, p. 271.

    Google Scholar 

  33. M.R. Plichta, W.A.T. Clark, and H.I. Aaronson: Metall. Trans. A, 1984, vol. 15A, pp. 427–35.

    CAS  Google Scholar 

  34. C. Yanar, J.M.K. Wiezorek, and W.A. Soffa: in Phase Transformations and Evolution in Materials, P. Turchi and A. Gonis, eds., TMS, Warrendale, PA, 2000, p. 39.

    Google Scholar 

  35. D.P. Hoydick: Ph.D. Thesis, University of Pittsburgh, Pittsburgh, PA, 1997

    Google Scholar 

  36. D.P. Hoydick, R.J. McAfee, and W.A. Soffa: in Boundaries and Interfaces in Materials, R.C. Pond, W.A.T. Clark, A.H. King, and D.B. Williams, eds. TMS, Indianapolis, IN, 1998, p. 269.

    Google Scholar 

  37. H. Gleiter, H. Mahajan, and K.J. Bachmann: Acta Metall., 1980, vol. 28, p. 1603.

    Article  CAS  Google Scholar 

  38. S. Mahajan, C.S. Pande, M.A. Imam, and B.B. Rath: Acta Mater., 1997, vol. 45, p. 2633.

    Article  CAS  Google Scholar 

  39. K.C. Russell: Acta Metall., 1969, vol. 17, p. 1123.

    Article  CAS  Google Scholar 

  40. J.W. Cahn: Acta Metall., 1956, vol. 4, p. 456.

    Google Scholar 

  41. J.E. Burke and B. Turnbull: Progs. Met. Phys., 1952, vol. 3, p. 220.

    Article  CAS  Google Scholar 

  42. E.S.K. Menon, M.R. Plichta, and H.I. Aaronson: Acta Metall., 1988, vol. 36, p. 321.

    Article  CAS  Google Scholar 

  43. J.H. Huang and P.C. Kuo: Mater. Sci. Eng., 1994, vol. B22, p. 256.

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. the Department of Materials Science, Carnegie Mellon University, 15213, Pittsburgh, PA

    C. Yanar (Postdoctoral Fellow)

  2. the Department of Materials Science and Engineering, University of Pittsburgh, 15261, Pittsburgh, PA

    J. M. K. Wiezorek (Assistant Professor) & W. A. Soffa (Professor)

  3. the Department of Physical Metallurgy, University of Belgrade, Belgrade, Yugoslavia

    V. Radmilovic (Professor)

  4. the National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, 94720, Berkeley, CA

    V. Radmilovic (Professor)

Authors
  1. C. Yanar
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. J. M. K. Wiezorek
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. W. A. Soffa
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. V. Radmilovic
    View author publications

    You can also search for this author in PubMed Google Scholar

Additional information

This article is based on a presentation made at the symposium entitled “The Mechanisms of the Massive Transformation,” a part of the Fall 2000 TMS Meeting held October 16–19, 2000, in St. Louis, Missouri, under the auspices of the ASTM Phase Transformations Committee.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Yanar, C., Wiezorek, J.M.K., Soffa, W.A. et al. Massive transformation and the formation of the ferromagnetic L10 phase in manganese-aluminum-based alloys. Metall Mater Trans A 33, 2413–2423 (2002). https://doi.org/10.1007/s11661-002-0363-3

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11661-002-0363-3

Keywords

Search

Navigation