Dislocation Damping due to Kink Motion

Abstract

The ultrasonic attenuation and velocity change that result from the damping due to motion of dislocation kinks have been calculated on the following assumptions: (1) the frequency of thermal creation of kinks is smaller than the frequency of the applied stress; (2) the frequency of thermal motion of the kinks is larger than the frequency of the applied stress. The characteristics of the attenuation calculated from the above assumptions differ from those of the string model for dislocation damping as follows. First, the resonance frequency depends on kink spacings and on the distance between pinning points on the dislocation. Second, for strain amplitude in excess of a critical value given in terms of kink spacings and the distance between pinning points, the attenuation decreases with increasing strain amplitude.