Alexander Vasilievich Stepanov (; August 26, 1908 – May 16, 1972) was a Soviet physicist and material scientist who pioneered the study of crystal deformation, the molecular structures of materials, studies on stress and breakage. He contributed to the development of composite materials. His technique for producing what are called shaped crystals was influential in the field of material studies and continues to be used, known as the "Stepanov method".

Life and work

Stepanov was born in

St. Petersburg Saint Petersburg, formerly known as Petrograd and later Leningrad, is the second-largest city in Russia after Moscow. It is situated on the River Neva, at the head of the Gulf of Finland on the Baltic Sea. The city had a population of 5,601, ...

where his father was a building technician. He graduated from the Leningrad Polytechnic Institute in 1930. He worked at the laboratory of Ivan Obreimov at Leningrad, followed by

Kharkiv Kharkiv, also known as Kharkov, is the second-largest List of cities in Ukraine, city in Ukraine.

, and still later at the lab of

Abram Ioffe Abram Fedorovich Ioffe ( rus, Абра́м Фёдорович Ио́ффе, p=ɐˈbram ˈfʲɵdərəvʲɪtɕ ɪˈofɛ; – 14 October 1960) was a prominent Soviet Union, Soviet physicist. He received the USSR State Prize, Stalin Prize (1942), the ...

. He spent some time at the optics laboratory headed by V. K. Fredericks. In 1937 he worked at the Pokrovskii Pedagogical Institute at Leningrad. He worked on growing perfect crystals to examine their structures, and mechanical properties including elasticity, strength,

anisotropy Anisotropy () is the structural property of non-uniformity in different directions, as opposed to isotropy. An anisotropic object or pattern has properties that differ according to direction of measurement. For example, many materials exhibit ve ...

and other aspects of solids. He developed optical polarization approaches to examine stresses. He introduced the use of

silver chloride Silver chloride is an inorganic chemical compound with the chemical formula Ag Cl. This white crystalline solid is well known for its low solubility in water and its sensitivity to light. Upon illumination or heating, silver chloride converts ...

as a model material for study. He attempted to extend his findings to develop a theory on fracture of materials including natural structures like wood and bones. He noted changes in thermal conductivity under

shear stress Shear stress (often denoted by , Greek alphabet, Greek: tau) is the component of stress (physics), stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross secti ...

es and connected melt heat and strain and in 1933 he noted the phenomenon of charge dislocation caused by plastic deformation of ionic crystals. In the 1940s he developed methods to produce monocrystal plates of zinc, aluminium and other metals. His methods have been used subsequently in the manufacture of

semiconductor A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping level ...

materials. Stepanov developed a method for producing crystals by pulling shapes from melts, supposedly inspired by observations of

water striders The Gerridae are a family of insects in the order Hemiptera, commonly known as water striders, water skeeters, water scooters, water bugs, pond skaters, water skippers, water gliders, water skimmers or puddle flies. They are true bugs of the ...

on the surface of water. He used plates with holes on the surface of metal melts to pull metal profiles with cross sections formed in the shapes of the holes. He believed that this would preserve crystal structure unlike methods involving rolling and extrusion. He attempted to get a Russian patent for this in 1940 and it was refused with claims that it was the same as Foucault's method for glass sheet pulling. Stepanov was a keen sportsman, took part in alpine skiing, played tennis and was a referee at soccer. He died in Crimea while on a Spring holiday for water skiing.

References

External links

Brief biography (in Russian) with portrait
{{DEFAULTSORT:Stepanov, Alexander 1908 births 1972 deaths Soviet physicists