Physical Substantiation of the True-Strainndash;Temperature Diagram for Polycrystalline bcc Metals

Abstract

We consider one of the possible versions of physical substantiation of the form of the true-strainndash;temperature diagram for polycrystalline bcc metals from the initial stages of plastic deformation to fracture within the temperature range from completely brittle fracture to the formation of a new grain structure as a result of dynamic recrystallization. We propose a model explaining the character of the temperature dependences of the critical strains corresponding to the transition from one type of dislocation structure to another under continuous loading. For the MChVP molybdenum alloy used as an example, we perform a comparative analysis of the theoretical and experimental temperature dependences of critical strains and demonstrate their good agreement. We also analyze the influence of factors determining the shape and location of the curves of critical strains in the true-strainndash;temperature diagram.