Influence of plastic deformation on the velocity and ultrasonic attenuation of copper single crystals

High-purity copper single crystal samples were plastically deformed between 0.02% and 1% in the [111] direction. The absolute ultrasonic velocity and attenuation related to the dislocations in copper single crystal were measured as a function of the plastic deformation. The amplitude-independent Swing Model far dislocation resonance was considered to obtain information about the evolution of the dislocation density (Lambda) with the degree of plastic deformation (epsilon%). The experimental data were interpreted as resulting from the contribution of two kinds of dislocations that lie in a cell structure. The results show a linear increase with the deformation of the density of dislocations (Lambda(1)) that lies in the cell walls [Lambda(1) (cm(-2)) approximate to 1.5 X 10(9) epsilon%]. The dislocation density inside the cell (Lambda(11)) is about two orders of magnitude lower than Lambda(1). (C) 2000 Elsevier Science S.A. All rights reserved.