Modèle pour les pics de frottement interne observés a haute température sur les monocristaux

Abstract

A model for internal friction peaks observed at high temperatures in single crystals A model is presented for treating internal friction peaks observed between 0-3 T _t and 0-6 T _t (T _t being the absolute melting temperature) in high purity copper and aluminium single crystals. The relaxation is related to the migration, by vacancy diffusion, of geometrical jogs along dislocation lines. In the case of peaks observed at about 0-3 T _t, the activation energy is close to one half of the self-diffusion energy, and it is supposed that vacancies diffuse along dislocation lines. In the case of higher temperature peaks the activation energy is close to the self-diffusion energy and corresponds to bulk vacancy diffusion. From this model it may also be seen that the peaks probably correspond to isolated dislocation climb and that the high temperature background is due to dislocations belonging to polygonization cells.