Temperature dependence of yield strength in terms of two components of stochastic shear stress field in glide plane in CrCoNiFeMn alloy

Abstract

The temperature dependence of the yield strength in the multicomponent CrCoNiFeMn alloy was investigated, using computer modelling and taking into account the short-wave and long-wave components of the shear stress field in the glide plane. The yield strength of a multicomponent alloy in the form of a concentrated solid solution without taking into account grain boundary strengthening is determined by three factors: the periodic lattice potential, the short-wave and long-wave components of the field of stochastic shear stresses in the glide plane, which are created by dissolved atoms. The force barriers resulting from the short-wave component will dominate. Overcoming them by dislocation with the assistance of applied stress and thermal activation will be a critical event to start dislocation movement. Barriers resulting from the periodic lattice potential and the long-wave component will be insignificant against the background of the short-wave component. Their effect on the yield strength can be taken into account by terms that do not depend on temperature. Thermal activation analysis of overcoming barriers resulting from a short-wave component, taking into account the probability of direct and reverse jumps through the barrier, gives the opportunity to describe the temperature dependence of the yield strength of a multicomponent alloy in a wide range of temperatures, including in the region of the high-temperature “plateau”. The dependence of the yield strength calculated in this way for the CrCoNiFeMn alloy correlates well with the corresponding experimental data. Keywords: temperature dependence, multicomponent alloy, glide plane, dislocation.