Serafim Nikolayevich Zhurkov (born 29.05.1905) is a Soviet physicist and an academician (1968; a corresponding member 1958). He was born in the village of Trubitkino in the former Tambov province. He graduated from Voronezh University (1929). Since 1930 he has worked at the Leningrad Physico-Technical Institute of the USSR Academy of Sciences, and from 1947 he has also been professor at Leningrad University.
His research is mainly in the field of the physics of strength (the experimental attainment of the theoretical strength of materials, and the elucidation of the atomic and molecular mechanism of the fracture of solids). He substantiated the assumption that local defects are the cause of the low practical strength, and established how the strength of filaments depends on their diameter. These data became the basis of the statistical theories of strength, in which the strength of a body is related to the probability that dangerous defects are present. He proved that the theoretical strength can really be attained.
Together with A. P. Alexandrov and P. P. Kobeko he laid the foundations of the study of the physico-mechanical and relaxation properties of polymers. He studied the part played by intermolecular interactions in the hardening (or softening) of polymers, and the effect of plasticisation on the hardness and the softening temperature of polymers. He developed the theory of the hardening of polymers, and proposed and experimentally substantiated the molecular mechanism of their vitrification.
Studying the mechanism of the fracture of solids, he derived a formula for the dependence of the lifetime on temperature and force, and radically changed the ideas about the mechanism of fracture. In the theory he developed he established that fracture is an atomic and kinetic process and that the strength of a body is determined not only by the forces of interatomic cohesion but also by the intensity of thermal motion. This gave rise to the idea that the strength of solids is kinetic in nature. He obtained data on the true local stresses on interatomic bonds, on the rupture of these bonds, on the secondary molecular degradation processes initiated by such ruptures, and on the appearance of embryonic discontinuities.
He founded a school in the physics of strength. Hero of Socialist Labour (1975). Editor-in-chief of the journal “Solid-State Physics”.