Vitaly Nikiforovich Gridnev (born 7.08.1908) is a Soviet physicist and an academician of the Academy of Sciences of the Ukrainian SSR (1967). He was born in the village of Uvarovo (now in the Tambov region). He graduated from the North Caucasus Institute of Metallurgy in Novocherkassk (1930). In 1931 — 41 he worked at the Dnepropetrovsk Institute of Metallurgy, in 1941—45 at the central works laboratory of the Magnitogorsk Metallurgical Combine and in 1945 —55 at the Kiev Polytechnic Institute (rector in 1952— 55). From 1955 he has been director of the Institute of Metal Physics of the Academy of Sciences of the Ukrainian SSR. His work concerns physical metallurgy, in particular phase transformations in iron and titanium alloys at ordinary and high rates of heating, and the nature of the brittle fracture of metals, chromium among them. He has studied the reversibility of martensitic transformations, the mechanism and kinetics of the formation of austenite in carbon and alloy steels, the tempering of quenched steel, and the nature of the transition of metals with a body-centred lattice into the brittle state. He laid the foundations of the rapid thermal strengthening of steels and alloys, which made it possible to develop new ways of producing high-strength materials. Under his direction a number of original methods were developed for the heat treatment of carbon steels and of titanium-based alloys with a metastable (quenched, deformed, irradiated) structure. The State Prize of the Ukrainian SSR (1974).