Advertisement

An Electron Microscope Study of Configurational Equilibrium at Twin-Grain Boundary Intersections in FCC Metals

  • R. J. Horylev
  • L. E. Murr

Abstract

A transmission electron microscopy study of 304 stainless steel films has been undertaken to systematically study the interrelationships of the degrees of freedom characterizing a grain boundary. From this study a configurational theory has been developed which is useful in explaining the existence of interfacial torques at twin-grain boundary intersections. The grain boundary misorientation (Θ) is defined as the relative rotation of the <110> directions in the adjacent grains of identical (110) orientation. The two remaining degrees of freedom are represented by the tilt or inclination (θ) and the asymmetry (Φ) of the grain boundary plane. Torques arise because of a difference in grain boundary energy with a change in misorientation or tilt. 90° twin configurations (twin plane along a <112> direction) are essentially high-torque situations, as a result of the change in misorientation (ΔΘ) between the twinned grain and its neighboring grain. 35° twins (twin plane along a <110> direction) are low-torque configurations, but can exhibit high torque anomalies when there is a sufficient variation in tilt across the intersection, Δθ. Misorientation, Θ, appears to be the dominant torque producing parameter for high-torque configurations, and dominates the variations in grain boundary free energy. Also, a functional relationship between Δθ and ΔΦ observed for both high-torque occurrences. Spreads in the histograms for twin boundary-grain boundary energy ratios are due to torque terms or variations in grain boundary energy with changes in grain boundary parameters.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    C.S. Smith, Trans. AIME, 175, 15, (1948).Google Scholar
  2. 2.
    C. Herring, in The Physics of Powder Metallurgy, ed. W.E. Kingston, McGraw-Hill Book Co., New York, 1951.Google Scholar
  3. 3.
    R.L. Fullman, J. Appl. Phys., 22, 448, (1951).CrossRefGoogle Scholar
  4. 4.
    M.C. Inman and A.R. Khan, Phil. Mag., 6, 937, (1961).CrossRefGoogle Scholar
  5. 5.
    M.C. Inman and H.R. Tipler, Met. Rev., 8, 105, (1963).Google Scholar
  6. 6.
    L.E. Murr, Acta. Met., 16, 1127, (1968).CrossRefGoogle Scholar
  7. 7.
    L.E. Murr, J. Appl. Phys., 39, 5557, (1968).CrossRefGoogle Scholar
  8. 8.
    L.E. Murr, R.J. Horylev and W.N. Lin, Phil. Mag., 22, 515, (1970).CrossRefGoogle Scholar
  9. 9.
    H. Brooks, in Metal Interfaces, ASM, Cleveland, Ohio, 1952, p. 20.Google Scholar
  10. 10.
    W.T. Read, Dislocations in Crystals. McGraw-Hill Book Co., New York, 1953.Google Scholar
  11. 11.
    L.E. Murr, Phys. Stat. Sol., 19, 7, (1967).CrossRefGoogle Scholar
  12. 12.
    L.E. Murr, R.J. Horylev and W.N. Lin, Phil. Mag., 20, 1245, (1969).CrossRefGoogle Scholar
  13. 13.
    L.E. Murr, Electron Optical Applications in Materials Science, McGraw-Hill Book Co., New York, 1970.Google Scholar
  14. 14.
    R.J. Horylev and L.E. Murr, in Proc. Electron Microscopy Soc, ed. C.J. Arceneaux, Claitor’s Publishing Division, Baton Rouge, 1970, p. 436.Google Scholar

Copyright information

© American Institute of Mining, Metallurgical and Petroleum Engineers, Inc. 1972

Authors and Affiliations

  • R. J. Horylev
    • 1
  • L. E. Murr
    • 1
  1. 1.Department of Materials ScienceUniversity of Southern CaliforniaLos AngelesUSA

Personalised recommendations