Barmin A. Structure and properties of iron based nano- and submicro-crystalline alloys

The thesis is devoted to studying the formation of nano- and submicrocrystalline structure in iron alloys of metallurgical and vacuum-condensation nature, as well as analyzing the thermal stability and physical-mechanical properties thereof. Using X-ray diffraction and transmission electron microscopy methods the structure was attested for iron based submicro- and nanocrystalline materials prepared by the following methods: mechanical-thermal treatment and electron beam evaporation followed by vacuum condensation. The effect of mechanical-thermal treatment on the grain structure dispersion and improving the mechanical properties of low-carbon steel has been established and analyzed. The technology was developed for preparation of iron based nano-structured alloys as films, foils, and coatings for hardening and increasing wear- and thermal resistance of machinery. For the first time it was established that tungsten alloying the iron films resulted in nano-structure formation due to segregation of alloying component at grain boundaries and sub-boundary areas. The mentioned structure features determine high level of strength and thermal stability of Fe-W foil structure. The model was proposed for structure dispersion process and stabilizing influence of tungsten small admixtures, which allows determining the optimal content of alloying component in vacuum condensates.