The effect of point-defect clouds on dislocation damping

Abstract

The theory is proposed of an amplitude-independent dislocation damping which takes into account a point-defect atmosphere. It is shown that the effective viscous-drag coefficient B* increases as C1/2 at low frequencies, and as C at high frequencies (C is a point-defect concentration). For high concentrations, B*>>B. For a strong renormalisation (B*>>B) there is an initial increase and subsequent decrease in internal friction. The results are in good agreement with the experimental features of the Simpson-Sosin peak in irradiated copper. It is suggested that the determination of the atmosphere formation time.