Instability of Plastic Deformation in Metals at Low Temperatures

Mathematical models of serrated plastic deformation in metals at ultra-low temperatures are developed. In the framework of the dislocation model, the instability of the plastic flow is shown to be caused by the relay mechanism of overcoming barriers (sub-boundaries, grain boundaries, etc.) by dislocation clusters. Regularities of localization of plastic deformation in alloys are described on the base of the model of interaction of dislocations with point defects. Within the scope of the thermodynamic model, it has been analytically and numerically established that in the range of helium temperatures, a change in the deforming stress, temperature, and plastic strain rate acquires an irregular stochastic nature. The obtained results are in good agreement with experimental data and can be used to construct the theory of plastic deformation of structural metals and alloys in the region of extremely low temperatures.