Description of the phenomenon of decreasing plasticity with increasing yield strength of polycrystal

Abstract

Using a three-level constitutive model, the influence of the crystal anisotropy factor, the hardening coefficient, the microscopic elastic limit and the distribution density function of the limiting elastic deformations of subelements on the shape of the deformation diagrams and the fracture conditions of a polycrystal is studied. Based on the theory of maximum normal stresses at the local level, a failure criterion was established at the macroscopic level, which includes all the parameters of the problem. The influence of the type of stress state and the geometric shape of the loading diagram on the magnitude of irreversible deformation preceding the initial process of destruction is investigated. From the established strength criterion follows the effect of a decrease in the plasticity of the material with increasing yield strength. The question of the critical value of the weight of destroyed subelements is discussed, at which a macrocrack forms, leading to the complete destruction of the body element.