HARDENING IN THE TRANSITION TO NANOCRYSTALLINE STATE IN PURE METALS AND SOLID SOLUTIONS (ULTIMATE HARDENING)

Abstract

The influence of the grain boundaries and solid solution on the variation in the yield stress in a wide range of grain sizes for pure metals, low-doped alloys, and multicomponent solid solutions, including high-entropy alloys, was analyzed. The generalized equation that describes the yield stress and hardness normalized to Young's modulus depending on the grain size using the averaging integrals was obtained. The achievement of the limiting values of hardening for nanostructured materials through the use of grain boundary engineering was considered. The concept of “useful” impurities intended to approximate the strength of such materials to the level compa-rable with the maximum (theoretically) possible one (Е/2π–Е/30) was proposed.