A New Technique for Distinguishing Internal Voids from Solid Inclusions

  • K. I. Maslov
  • T. Kundu
  • O. I. Lobkis


An acoustic microscope has been proven to be a very effective tool for visualization and characterization of small internal defects in solids[l]. The distinction of internal defects such as cracks and voids from solid inclusions is sometimes necessary for material evaluation. For example in case of light metal casting alloys ultrasonic scattered echo from pores and heavy metal inclusions used for strengthening purposes can give the ultrasonic signal of the same order of magnitude [2]. In this paper it is shown how the phase information of the reflected echo can be used to distinguish void signals from solid inclusion signals. Conventional acoustic imaging techniques that use only amplitude information and ignores the phase information can not distinguish between voids and inclusions.


Longitudinal Wave Reflection Coefficient Spherical Inclusion Solid Inclusion Spherical Void 
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  1. 1.
    A. Briggs, “Acoustic Microscopy”, Clarendon Press, Oxford, 1992.Google Scholar
  2. 2.
    J. Krautkramer, H. Krautkramer “Ultrasonic testing of materials” Springer-Verlag, Berlin Heidelberg, N.Y. 1983., p. 536.Google Scholar
  3. 3.
    L.M. Brekhovskikh, “Waves in layered media” Academic Press, N.Y., 1960.Google Scholar
  4. 4.
    W. A. Simpson Jr., “Time-Frequency-Domain Formulation of Ultrasonic Frequency Analysis”, J. Acoust. Soc. Am. 5 (6) pp. 1776–1781, (1974).CrossRefGoogle Scholar
  5. 5.
    D.E. Fitting, L. Adler, “Ultrasonic Spectral Analysis for Nondestructive Evaluation”, Plenum, N.Y. 1981, pp. 106–109.Google Scholar
  6. 6.
    N. Nakaso, K. Ohira, M. Yanaka, Y. Tsukahira, “Measurement of acoustic reflection coefficient by an ultrasonic microspectrometer”, IEEE trans, ultrason, ferroelectr. Freq. Control, 41 (4) pp. 494–502, (1994).CrossRefGoogle Scholar
  7. 7.
    C.F. Ying and R. Truell, “Scattering of a plane longitudinal wave by a spherical obstacle in an isotropically elastic solid”, J. Appl. Phys. 27, pp. 1086–1097, (1956).MathSciNetMATHCrossRefGoogle Scholar
  8. 8.
    N.G. Einspruch, E.J. Witterholt and R. Truell, “Scattering of a plane transverse wave by a sphrrical obstacle in an elastic medium”, J. Appl. Phys., 31, pp.806–818 (1960).MathSciNetMATHCrossRefGoogle Scholar
  9. 9.
    J.E. Gubernatis, E. Domany, J. A. Krumhansl, M. Huberman, “The Born Approximation in the Thery of the Scattering of Elastic Waves by Flaws”, J.of Appl. Phys., 48 (7), pp.2812–2819 (1977).CrossRefGoogle Scholar
  10. 10.
    B.R. Tittmann, R.E. Cohen. J.M. Rochardson, “Scattering of Longitudinal Waves I ncident on Spherical Cavity in a Solid”, J. Acoust. Soc. Am. 63 (1) pp. 68–74, (1978).CrossRefGoogle Scholar
  11. 11.
    A. Stockmann, P.S. Nocholson, “Ultrasonic Characterization of Model Defects in Ceramics—Voids in Glass—Theory and Practice”, Mat. Eval., 44, pp.756–761, (1986).Google Scholar
  12. 12.
    A. Stockmann, P. Mathieu, P.S. Nocholson, “Ultrasonic Characterization of Model Defects in Ceramics (part 3). Spherical Inclusion in Opaque Crystallized Glass — Theory and Practice, Materials Evaluation”, 47 (3) pp. 356–362, (1989).Google Scholar
  13. 13.
    O.I. Lobkis and P.V. Zinin, “Acoustic microscopy of spherical objects. Theoretical approach”, Acoust. Lett. 14, 168–172,(1991).Google Scholar
  14. 14.
    O.I. Lobkis, T. Kundu, and P.V. Zinin “A theoretical analysis of acoustic microscopy of spherical cavities”. Wave Motion 21, pp. 183–201, (1995).MATHCrossRefGoogle Scholar
  15. 15.
    L. Paradis, J.F. Salin, “Non destructive evaluation of the mechanical characteristics of plasma sprayed ceramic coatings” in Review of progress in quantitative nondestructive evaluation, 13B eds. D.O. Thompson and D.E. Chimenti, Plenum N.Y. 1994, pp. 1229–1236.Google Scholar
  16. 16.
    O.V. Kolosov, O.I. Lobkis, K.I. Maslov, P.V. Zinin, “The effect of the focal plane position on the images of spherical objects in the reflection acoustic microscope”, Acoust. Lett. 16, pp. 84–88 (1992).Google Scholar
  17. 17.
    O.I. Lobkis, K.I. Maslov, T. Kundu, P.V. Zinin, “Spherical Inclusion Characterization by the Acoustic Microscope: Axisymmetric Case”, J. Acoust. Soc. Am, in press (1995).Google Scholar
  18. 18.
    Y. Sasaki, T. Endo, T. Yamagishi and M. Sakai, “Thickness measurement of a thin film layer on an anisotropic substrate by phase-sensitive acoustic microscope”, IEEE Trans. UFFC. 39, pp. 638–642 (1992).Google Scholar

Copyright information

© Plenum Press, New York 1996

Authors and Affiliations

  • K. I. Maslov
    • 1
  • T. Kundu
    • 2
  • O. I. Lobkis
    • 1
  1. 1.Institute of Chemical PhysicsRussian Academy of ScienceMoscowRussia
  2. 2.Department of Civil Engineering and Engineering MechanicsUniversity of ArizonaTucsonUSA

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