In-Situ Monitoring of Dislocation Mobility

  • Masahiko Hirao
  • Hirotsugu Ogi

Abstract

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
$$ \alpha = \left( {\frac{{4GB{{\left| b \right|}^2}{\omega ^2}}}{{{\pi ^6}{C^2}}}} \right)\Lambda {L^4} $$
(6.1)
,
$$ \frac{{V - {V_0}}}{{{V_0}}} = \left( {\frac{{4GB{{\left| b \right|}^2}}}{{{\pi ^4}C}}} \right)\Lambda {L^2} $$
(6.2)
.

Keywords

Shear Wave Longitudinal Wave Point Defect Velocity Change Dislocation Mobility 
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.

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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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