Trefilov and Strength Physics Today

Abstract

The paper presents the main topics of the plenary lecture given at the 49th International Conference ‘Actual Problems of Strength’ (Kiev, June 14–17, 2010) dedicated to the 80th birthday anniversary of Academician V. I. Trefilov. Special attention is paid to change in the dependence of the yield stress on grain size in transition from the microstructured to the nanostructured state. It is shown that S-functions can be used to obtain a generalized equation for the dependence of the yield strength on grain size with regard to changes in the mechanisms of hardening of polycrystals in the vicinity of grains with critical sizes d_cr1 and d_cr2. This equation enables us to describe softening effects in transition to nanostructures (the so-called ‘negative’ trend of the Hall–Petch relation) and abrupt hardening under increased intergranular cohesion.