Nakonechna O. Intermetallics, transition metal carbides and nanocomposites on their base formation feature and properties

Doctoral thesis combines three directions of experimental researches in the frame of uniform concept of crystal state formation: 1) study of phase equilibria and features of crystal structures of ternary gallides of REM formation, 2) definition of the mechanism of carbide phases formation from Me-CNT charge and directly in the metal matrix at nanocomposite material fabrication; 3) study of the microstructure, mechanical characteristics and corrosion resistance of TiAlSiN and TiAlCrN thin solid films, obtained by cathodic-arc method. Isothermal cross sections of phase diagrams of Ti-Al-Ga, Ni-Al-Ga and Y-Cu-Ga ternary metal systems are constructed in full concentration interval, and the features of formation and physical characteristics of series of closely related compounds of Me(Me,Ga)4 and Me(Me,Ga)3 compositions, which exist in the systems of{Y, Dy}-Cu-Ga, Gd-Al-Ga and Dy-Mn-Ga are established (1). The scientific concept of the mechanism of formation of TiC, ZrC, HfC, VC, NbC, TaC, W2C, Mo2C, Fe3C, Co3C, NiCx carbide phases at their mechanochemical synthesis with the carbon nanotubes (CNT) as a component of the charge has developed, according to which the carbon phases are formed by a self-sustaining reaction. The synthesis conditions and properties of nanocomposite materials obtained by compacting the mechanically alloyed charge of Fe-Ti-CNT, Ti-Cu-CNT and Y-Cu powders at the first technological stage are considered. Basic regularities and physical mechanisms of formation of reinforcing nanoparticles of carbides and oxides directly in the metal matrix of the composite are established. Microstructure and mechanical characteristics of TiAlSiN and TiAlCrN thin films obtained by vacuum-arc method (3) were studied by modern research methods. The effect of Si and Cr dopants on the mechanical characteristics of thin solid single- and multilayerd coatings of the TiAlN system has studied. For the first time, TiAlSiN thin films with a graded composition were obtained and a comprehensive study of their microstructure and mechanical characteristics was performed. The mechanisms of crack formation in thin films TiAlSiN and TiAlCrN are established, for the explanation of which an energy model is proposed, which is based on the calculation of the irreversible dissipative work of the load on the indenter. The corrosion resistance of coatings has been studied in detail and the structure of the layered oxide scale formed on the surface of the coating at high-temperature annealing has been studied for the first time.