Sadanov Y. Structural characteristics, ultimate strength, and radiation resistance of nano and pico-sized objects

The dissertation is devoted to: the study of the structural and emission characteristics of metallic and carbon nano- and pico-sized objects under of superstrong electric fields the determination of the formation features of field emission images of pointed objects at their size reduction to subnanometer level, the development of high-field fabrication methods and mechanical loading of nano- and pico-sized objects to determine their strength, the investigation of thermal and radiation resistance of such objects. A high-field method for manufacturing extremely small pointed objects - monoatomic carbon chains (carbines) has been implemented. An extremely high level of resolution of field emission images has been achieved on the chains. The images of the upper atoms of the chains in the form of molecular orbitals were obtained. For the first time the dimeric carbon chains and elementary subnanotubes, which stability are predicted theoretically, have been experimentally discovered by ultra-high resolution. The emission properties of carbine chains are investigated and the linearity of their current-voltage characteristics in the Fowler-Nordheim coordinates is established. The strength of monatomic carbon chains and graphene nanosheets was experimentally determined by the Maxwell surface forces loading. The ultimate strength of tungsten and molybdenum nanoobjects was measured and the values of the cohesive strength of grain boundaries were obtained. The erosion of the tungsten surface under low-energy helium irradiation is investigated. The phenomenon of long-range interaction of own interstitial atoms with adatoms of radiation origin was discovered. The evolution of surface radiation defects under irradiation was investigated by methods of mathematical computer modeling. The process of collective movement of significant surface atoms groups is revealed. This process provides the radiation-stimulated self-healing of surface vacancies linear clusters and can be described in terms of delocalized surface vacancies - voidions. A high-field method for the experimental determination of the energy of formation of interstitial atoms at grain boundaries has been developed. It made possible to conclude the grain-boundary mobility of interstitial atoms is low. The analysis of the accumulation of radiation vacancies in tungsten nanocrystals of various sizes is carried out. The obtained data indicates the migration of own interstitial atoms in the volume is one-dimensional.