Physics of deformation and destruction of the surface layers of materials

In this report the kinetic model of diffuse-limited propagation of dislocation loops in conditions of periodical crystal compression is proposed. It is shown that vacancy satiety, which originates by crystal compression, results in creation of vacancy clusters and dislocation loops. Main factors were analyzed responsible for anomalous features of plastic tlow in the subsurface material layers from the viewpoint of structural-energy features of nucleation, multiplication and thermoactivated dislocation motion near the free surface of solids. Calculation and experiments have shown that stress of homogenous and heterogenous nucleation of dislocations near free surface as a rule is considerably lower than that for the crystal volume. It has been also shown that dislocation velocities and main thermoactivation parameters of their motion in crystal below and above macroscopic yield point considerably differ. Major reason have been analyzed being responsible for the phenomenon.