Physical nature of the temperature dependence of yield stress

Abstract

Below is one of the most significant works by V. I. Trefilov and Yu. V. Mil’man. The idea that the temperature dependence of the yield stress is determined by the thermally activated escape of potential barriers by dislocations is used to derive an equation that includes, as a particular case, the Seeger equation that describes the linear dependence of the yield stress on low temperatures and the Haasen equation that represents the exponential temperature dependence of the yield stress. The equation derived was later used to describe brittle-ductile transition and introduce the so-called deformation temperature at which the yield stress begins to strongly depend on temperature and strain rate and the ductile and brittle ranges are separated. These ideas were widely used to examine the deformation and fracture mechanisms for a range of promising materials with contained plasticity (refractory metals, ceramic materials, covalent crystals, quasicrystals, sintered materials).