In-Situ Monitoring of Dislocation Mobility

  • Masahiko Hirao
  • Hirotsugu Ogi


Dislocations are pinned by point defects such as vacancies and interstitials. They vibrate anelastically responding to the ultrasonic wave and absorb its energy, resulting in increase of attenuation a and decrease of modulus. Granato and Lücke (1956) established a dislocation-damping theory to relate the ultrasonic velocity and attenuation with dislocation characteristics such as the segment length L and density Λ. The detailed expressions appear in their original paper and in many monographs (for example, Mason, 1958; Truell et al., 1969). For frequencies well below the resonance frequency of a single dislocation-segment line, they can be reduced to
$$ \alpha = \left( {\frac{{4GB{{\left| b \right|}^2}{\omega ^2}}}{{{\pi ^6}{C^2}}}} \right)\Lambda {L^4} $$
$$ \frac{{V - {V_0}}}{{{V_0}}} = \left( {\frac{{4GB{{\left| b \right|}^2}}}{{{\pi ^4}C}}} \right)\Lambda {L^2} $$


Shear Wave Longitudinal Wave Point Defect Velocity Change Dislocation Mobility 
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Copyright information

© Springer Science+Business Media New York 2003

Authors and Affiliations

  • Masahiko Hirao
    • 1
  • Hirotsugu Ogi
    • 1
  1. 1.Osaka UniversityJapan

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