Changes in internal friction and dislocation charge in sodium chloride crystals following plastic deformation

Abstract

Measurements of the elastic compliance, the internal friction, and the induced dislocation voltage during deformation recovery indicate that the dislocation damping factor remains constant, while pinning and charging of the dislocation core occur by diffusion. The activation energy for charging by diffusion is 0.45 eV and for the pinning process is 0.65 eV.

EMATs for Science and Industry

“…They proposed a theory (GHL theory) that combined the vibrating-string model ) and the migration model for impurity atoms given by Cottrell and Bilby (1949). GHL theory was consistent with measurements at early stages of the recovery, and several researchers used it to study the diffusion of point defects towards dislocations (Phillips and Pratt, 1970;Anderson and Pollard, 1979). It, however, fails to explain long-time recovery, because the Cottrell-Bilby model neglects saturation ofthe pinning points on a dislocation.…”