Vitaly Ivanovich Danilov (10.04.1902-19.03.1954) was a Soviet physicist and an academician of the Academy of Sciences of the Ukrainian SSR (1951). He was born in the village of Zheltoye (now in the Voroshilovgrad region). He graduated from Dnepropetrovsk University (1926). In 1933—44 he was head of a laboratory at the Dnepropetrovsk Physico-Technical Institute and at the same time, in 1930—35, head of a department at the Dnepropetrovsk Chemico-Technological Institute and in 1935—41 at Dnepropetrovsk University. From 1945 he was head of a department at the Laboratory of Metal Physics of the Academy of Sciences of the Ukrainian SSR (director from 1951).
His research was mainly on the X-ray study of the structure of liquids, in particular of metals and alloys, and on the processes of crystallisation. He formulated ideas about their structure. He showed that different liquid metals have different packings of atoms and that monatomic liquids may have various structures differing considerably from close packing.
He settled a number of fundamental questions about the passage of a substance from the liquid state into the solid, and studied the physics of the formation of crystallisation centres and the effect of various factors on it, in particular that of insoluble impurities. He discovered the activation and deactivation of impurities and showed that these two processes determine the kinetics of crystallisation and the formation of the cast structure. He showed that crystallisation rests on the spontaneous formation of crystallisation centres and that impurities, although an important factor affecting that formation, are a secondary one. He formulated criteria for spontaneous crystallisation and proposed a classification of liquids according to their tendency to crystallise spontaneously. USSR State Prize (1950).