Experimental Evidence of Kink Relaxation and Kink Resonance in Dislocations of FCC Metals

Abstract
Many papers have been devoted to the motion of dislocation lines in crystals. The string model and the kink model presented the most relevant theoretical approach. However, each model independently can not describe all experimental data. In this paper is presented experimental data of logarithmic decrement associated to dislocation lines, measured in Hz and MHz ranges, on high purity copper single crystals plastically deformed by compression and torsion at room temperature. The experimental data obtained for the Bordoni Peak, analyzed on the basis of the kink model, shows the predicted temperature dependence of the effective enthalpy, a evidence of the kink diffusion mechanism. The data can be well fitted over all temperature range investigated, assuming the contribution of kink relaxation and kink resonance aging simultaneously. From the last mechanism a temperature dependent kink density is assumed. This procedure allows to explain the width and the asymmetry of the Bordoni peak.