Advertisement

Journal of Materials Science

, Volume 27, Issue 16, pp 4261–4281 | Cite as

Influence of some alloying elements on decomposition of a Co-3wt% Ti alloy

  • J. Singh
  • C. Suryanarayana
Review

Abstract

The effect of minor alloying additions (La, Fe and Nb) on the decomposition behaviour of a Co-3 wt%Ti alloy is discussed. Optical microscopy coupled with electron microscopy and diffraction have aided in elucidating the microstructural evolution in these alloys. The solid solutions of binary and ternary alloys decomposed on ageing by the spinodal mode. The different stages of coarsening of the precipitates are discussed, as are kinetics and morphological changes during precipitation of binary and ternary alloys. After long ageing times, discontinuous precipitation set in. The discontinuous product is close to equilibrium and is considered to be driven by the difference between coherent and incoherent equilibria in these systems. Coherent precipitation occurred by volume diffusion whereas incoherent precipitation reactions were determined by grain-boundary diffusion. The microstructural evolution has been correlated with the observed variation in hardness and yield strength at different stages of decomposition.

Keywords

Precipitation Solid Solution Yield Strength Optical Microscopy Microstructural Evolution 
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.

Nomenclature

Ts

Critical temperature for coherent spinodal decomposition

λ

Wavelength of modulations

K

Rate constant

γ

Interfacial energy

ρ

Density of alloy

W

Weight fraction

M

Atomic weight

Vm

Molar volume of Co3Ti

a

Lattice parameter of matrix

N

Avogadro's number

ap

Lattice parameter of precipiate

Δa

Mismatch lattice parameter

S

Size of precipitate for loss of coherency

Vv

Volume fraction of precipitate

t

Foil thickness

Vv′

Apparent volume fraction

D

Measured precipitate size

Ce

Solvus composition

A

Constant

B

Constant

A

Amplitude of modulation

n

Distortion parameter

Y

Young's modulus

b

Burgers vector

β

Wave vector

σc

Critical resolved shear stress

Z

Spacing of misfit dislocations

ass

Lattice parameter of solid solution

C

Concentration in atomic fraction

b0

Constant

b1

Constant

b2

Constant

YS

Yield strength

Db

Grain-boundary diffusivity

Dv

Volume diffusivity

pchem

Chemical driving force

X0

Composition of supersaturated alloy

Xe

Equilibrium concentration

V

Growth velocity

b

Interatomic distance

f

Fraction of driving force

ΔG

Gibb's free energy

n

Misfit parameter

F

Traction force

r0

Radius of lamellar rods

N

Number of rods per unit area

G

Growth of discontinuous precipitation (cell)

Xm

Matrix composition ahead of interface

Xβ

Composition of second phase (Co3Ti)

Q

Activation energy

Γ

Effective thickness of boundary

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    E. Diderrich, J. M. Drapier, D. Coutsrdis and L. Habraken, Cobalt 1 (1975) 7.Google Scholar
  2. 2.
    D. M. Davies and B. Ralph, J. Microscopy 96 (1972) 987.CrossRefGoogle Scholar
  3. 3.
    A. J. Ardell and R. B. Nicholson, Acta Metall. 14 (1966) 1295.CrossRefGoogle Scholar
  4. 4.
    R. W. Fountain and W. D. Forgeng, Trans. TMS-AIME 215 (1959) 998.Google Scholar
  5. 5.
    R. W. Fountain, G. M. Faulring and W. D. Forgeng, ibid. 221 (1961) 747.Google Scholar
  6. 6.
    H. Bibring and J. Manenc, Compt. Rend. Acad. Sci. Paris 249 (1959) 1508.Google Scholar
  7. 7.
    Ye. K. Zakharov and B. G. Lifschitz, English Abstracts of Selected Articles from Soviet Block and Mainland China Technical Journals, Series IIIm (1960).Google Scholar
  8. 8.
    A. L. Berezina and K. V. Chuistov, Phy. Met. Metallogr. 22(3) (1966) 84.Google Scholar
  9. 9.
    Idem., ibid. 27(2) (1969) 189.Google Scholar
  10. 10.
    O. Ye. Tkachenko and K. V. Chuistov, ibid. 29(4) (1972) 159.Google Scholar
  11. 11.
    M. I. Zakharova and N. A. Vasil'yeva, ibid. 33(5) (1972) 119.Google Scholar
  12. 12.
    M. N. Thompson, PhD thesis, University of Cambridge, UK (1971).Google Scholar
  13. 13.
    M. N. Thompson and J. W. Edington, “Microscopie Electronique”, Vol. 2 (Favart, Paris, 1970) p. 545.Google Scholar
  14. 14.
    Idem. in “Second International Conference on the strength of Metals and Alloys”, Asilomar, CA (1971) p. 1150.Google Scholar
  15. 15.
    J. M. Blaise, P. Viatour and J. M. Drapier, Cobalt 49 (1970) 192.Google Scholar
  16. 16.
    B. J. Piearcey, R. Jackson and B. B. Argent J. Inst. Met. 91 (1962) 257.Google Scholar
  17. 17.
    D. E. Laughlin and J. W. Cahn, Acta Metall. 23 (1975) 329.CrossRefGoogle Scholar
  18. 18.
    P. E. J. Flewitt, ibid. 22 (1974) 47.CrossRefGoogle Scholar
  19. 19.
    J. Singh, C. M. Wayman, J. Mazumder, S. Ranganathan and S. Lele, Met. Trans. A19 (1988) 1703.CrossRefGoogle Scholar
  20. 20.
    H. Kubo and C. M. Wayman, ibid. A10 (1979) 633.CrossRefGoogle Scholar
  21. 21.
    F. H. Wohlbier (Ed.), “Diffusion and Defect Data”, Vol. 13 (Trans. Tech. Publ., Aedermannsdorf, Switzerland, 1976) p. 34.Google Scholar
  22. 22.
    I. M. Lifshitz and V. V. Slyozov, J. Phys. Chem. Solids 19 (1961) 35.CrossRefGoogle Scholar
  23. 23.
    C. Wagner, Z. Electrochem. 65 (1961) 581.Google Scholar
  24. 24.
    A. J. Ardell, Met. Trans. 1 (1970) 525.CrossRefGoogle Scholar
  25. 25.
    W. B. Pearson, “The Crystal Chemistry and Physics of Metals and Alloys” (Wiley Interscience, New York, 1972). p. 151.Google Scholar
  26. 26.
    B. G. Lefevre, A. T. D'Annessia and D. Kalish, Met. Trans. A9 (1978) 577.CrossRefGoogle Scholar
  27. 27.
    L. H. Schwarts and J. T. Plewes, Acta Metall. 22 (1974) 911.CrossRefGoogle Scholar
  28. 28.
    J. W. Cahn, ibid. 14 (1966) 477.CrossRefGoogle Scholar
  29. 29.
    W. Gust, B. Predel and Tat. T. Nguyen, Z. Metallkde 67 (1976) 10.Google Scholar
  30. 30.
    J. W. Chan, Acta Metall. 11 (1963) 1275.CrossRefGoogle Scholar
  31. 31.
    N. F. Mott and F. R. N. Nabarro, Proc. Phys. Soc. 52 (1940) 86.CrossRefGoogle Scholar
  32. 32.
    E. Orowan, in “Symposium on Internal Stresses in Metals and Alloys” (Institute of Metals, London, 1948) p. 451.Google Scholar
  33. 33.
    R. J. Livak and G. Thomas, Acta Metall. 19 (1971) 497.CrossRefGoogle Scholar
  34. 34.
    S. D. Dahlgren, Met. Trans. A8 (1977) 347.CrossRefGoogle Scholar
  35. 35.
    R. I. Saunderson, P. Wilkes and G. M. Lorimer, Acta Metall. 26 (1978) 1357.CrossRefGoogle Scholar
  36. 36.
    J. Singh and G. R. Purdy, J. Mater. Sci. 22 (1987) 2918.CrossRefGoogle Scholar
  37. 37.
    I. G. Solorzano and G. R. Purdy, Met. Trans. A15 (1984) 1055.CrossRefGoogle Scholar
  38. 38.
    D. A. Porter and J. Edington, Proc. R. Soc. 358A (1977) 335.Google Scholar
  39. 39.
    A. Pervoic and G. R. Purdy, Acta Metall. 29 (1982) 53.CrossRefGoogle Scholar
  40. 40.
    M. Hillert, Met. Trans. 3 (1972) 2729.CrossRefGoogle Scholar
  41. 41.
    K. N. Tu and D. Turnbull, Acta Metall. 15 (1967) 369.CrossRefGoogle Scholar
  42. 42.
    R. A. Fournelle and J. B. Clark, Met. Trans. 3 (1972) 2757.CrossRefGoogle Scholar
  43. 43.
    N. Lange and G. R. Purdy, “Report of Royal Institute Technology”, Stockholm (1967).Google Scholar
  44. 44.
    D. B. Williams and E. P. Butler, Int. Met. Rev. 26 (1981) 153.CrossRefGoogle Scholar
  45. 45.
    C. Zener, Trans. AIME 167 (1946) 550.Google Scholar
  46. 46.
    H. I. Aaronson and J. B. Clark, Acta Metall. 16 (1968) 845.CrossRefGoogle Scholar
  47. 47.
    D. Turnbull, ibid. 3 (1955) 55.CrossRefGoogle Scholar
  48. 48.
    Y. C. Liu and H. I. Aaronson, ibid. 16 (1968) 1343.CrossRefGoogle Scholar
  49. 49.
    M. Korchynsky and R. W. Fountain, Trans. Met. Soc. AIME 215 (1959) 1033.Google Scholar
  50. 50.
    H. Tsukakino and R. Nozato, J. Mater. Sci. 19 (1984) 3013.CrossRefGoogle Scholar
  51. 51.
    J. Singh, S. Lele and S. Ranganathan, J. Mater. Sci. 15 (1980) 2010.CrossRefGoogle Scholar

Copyright information

© Chapman & Hall 1992

Authors and Affiliations

  • J. Singh
    • 1
  • C. Suryanarayana
    • 2
  1. 1.GE Aircraft EngineCincinnatiUSA
  2. 2.Institute for Materials and Advanced ProcessesUniversity of IdahoMoscowUSA

Personalised recommendations