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Information × Registration Number 0205U007063, 0104U003132 , R & D reports Title Formation, physical and mechanical properties of nanostructure that was formed on bulk metall materials by both mechanical and chemical treatments popup.stage_title Head Belots'ky Aleksey Vasilevich, Registration Date 15-12-2005 Organization National Technscal University of Ukraine "Kiev Polytechnic Institute". popup.description2 The specific features of structural state, phase composition, parameters of grain and dislocation structure and mechanical behaviour of iron subjected to severe plastic deformation (SPD) under diffusion flow of dissolved dopant element and occurred due to friction with gas atmosphere, were investigated by using complex of modern methods of physical metallurgy - metallographic and X-ray diffraction analysis, transmission electron microscopy and methods of micromechanical tests. Microstructure features of various sections in the surface layer, from strain-free matrix to the treated top surface of iron, subjected to SPD by friction with ammonia, were systematically characterized. It is concluded that grain refinement process and directional mass transfer of dissolved atomic nitrogen in iron influence by each other, facilitating the evolution of deformation-induced structure and resulting in improvement of nitriding efficiency. Based on the experimental evidences about dislocation and grain structure changing a grain refinement mechanism was proposed. It was shown appreciable effect of ultra fine refining the grain structure on material response to deformation. Mechanical behaviour of iron alloys with fine grained deformation structure induced by SPD could be influenced by several structural parameters, i.e. dissolved dopant elements, dislocations and other stacking faults, grain boundaries, secondary phase. Mechanical parameters such as Young's modulus, nanohardness, and plasticity characteristic were found to be of high sensitive both to the scale of grain structure and to iron modification by nitrogen. Product Description popup.authors popup.nrat_date 2020-04-02 Close