Physical Theory of Plasticity and Strength

JRENG the 50 years elapsed since the discovery (in 1912) of diffraction of x rays by crystals and the development of the dynamic theory of the crystal lattice (1915), the physics of plasticity and strength has turned from a descriptive science with only formal premises into a major division of solid state physics, based on reliable experimental researches and on fully developed theoretical notions.The development of the physical theory of plastic deformation and failure is closely connected with the work of J. I. Frenkel, whose varied interests included basic problems in the theory of mechanical properties of both crystalline and non-crystalline solids.The present development of theoretical ideas and experimental methods of research on the real structure of solids has prepared the ground for the decisive stage in the development of the physics of plasticity and strength, namely the direct investigation of the atomic mechanism of plastic deformation and failure.This is most clearly pronounced in the case of crystalline bodies.