ФОРМИРОВАНИЕ НАНОСТРУКТУРНЫХ ТОПОКОМПОЗИТОВ С КЛАСТЕРНО-ГРАДИЕНТНОЙ АРХИТЕКТУРОЙ КОМБИНИРОВАННОЙ ИОННО-ВАКУУМНОЙ ОБРАБОТКОЙПолещенко К.Н. 1 , Коротаев

The article updates the long-range action effect in the formation of nanostructured topocomposites under the conditions of the ion-plasma impact. The authors study the features of the concentration dependences of the distribution of elements in the boundary layers in the formation of the two-layer system "film-base". They determine that under the conditions of the implementation of the cascade cross-effect at considerable depths in the material of the hard-alloy base, locally inhomogeneous areas are formed, resulting in an increase in the microhardness of the material. Within the framework of the worked out simulation model, the study of factors contributing to the manifestation of the long-range action effect is undertaken. The contribution to the change of concentration dependences of the temperature, different diffusion mechanisms and the pressure gradient is established and differentiated. Based on the synthesis and analysis of the dynamics of the competing processes of "deceleration - acceleration" of the diffusion, the explanation to the formation of the hardened sublayers in the hard-alloy base of topocomposites and their role in the manifestation of the long-range action effect is offered.

The article considers the wear resistance and wear peculiarities of nanostructured topocomposites with the clustered gradient architecture. The authors regard the specificity of the impact of the cluster morphology on the contact interaction under microcutting conditions. They study the causes of persistence of the high wear resistance for the given class of nanostructured topocomposites. The mechanisms of energy dissipation from the tribocontact zone due to their nanogeometry and the structural-phase structure are analyzed. The contribution of triboactivated diffusion and deformation processes to providing the increased wear resistance of topocomposites on the hard-alloy basis is differentiated. Their approbation in the conditions of edge cutting processing of heat-resistant titanium alloy is carried out.

The article proposes an improved system of ion-plasma modification based on the use of three cathodes installed at different angles. Using the methods of scanning electron microscopy and energy dispersion analysis, the authors study the morphology, the composition of elements and the coating structure in terms of titanium nitride formed by ion-plasma modification with a change in processing time. They find that there is no drop phase of metallic titanium, adversely affecting the mechanical properties in the coating formed on the studied technological regimes of ion-plasma processing. An experimental assessment of the destruction of nanostructured ion-plasma coatings on the structural parts of pipeline fittings operating under fretting corrosion is carried out.

The article proposes an approach to solving the problem of increasing fretting resistance of lock joints of blades for gas turbine engines through the creation of nanostructured topocomposites with the surface layers in a metastable state having a low shear stability in terms of vibrofriction. The authors implement the method of vacuum combined ion-plasma processing, which allows forming the surface layers of the material with mixed amorphous-nanocrystal structure and purposeful controlling the surface morphology. They show that the proposed flow diagram allows developing the required morphology from the arrays of nano-sized conglomerates of the “asperity – cavity” type on the surface. A comparative study of fretting resistance of nanostructured topocomposites in terms of vibrofriction is carried out. It is established that the specificity of their wear is to reduce the wear rate at the initial stage.

The article considers physico-technological aspects of receiving nanostructural topocomposite coatings in terms of the cascade cross effect based on the special cathodic system, making possible ionic-plasma processing simultaneously with the use of three cathodes in a pulse mode. The authors carry out theoretical and experimental researches of forming concentration profiles of element distribution in surface layers of the bilayer "film-base" system. They determine the features of mass transfer processes developing in response to cascade cross effect. It is demonstrated that due to the mutual diffusion of the film and the base elements in the field of the phase boundary in the "film-base" system a transition area is formed. Its dimensions can be associated with the thickness of the nanofilm. The authors give an example of receiving a multilayer nanostructural composition in terms of cascade cross effect.

The article regards formation processes of activation and dissipative energy flows under ion-plasma sputtering of coatings. It proposes an advanced system of ionic-plasma processing with the activation of the processed surface by high voltage pulses of electric potential. The authors carry out the experimental evaluation of tribological properties for the samples with coatings and study the features of their surface damage. It is established that the topokompozitny coverings, containing high-disperse nanodimensional clusters reduce probability of brittle destruction during an initial stage of operation of tribocouplings. They show that the use of high-frequency pulse oscillations under ion-plasma sputtering decreases friction ratio and increases wear resistance of coatings.

Results of a research of influence of materials of the alloying electrodes at electrospark modifying of steel products on phase structure of the formed coverings and blankets are presented. It is established that when processing the electrode on the basis of carbide of the titan with additives of nickel, chrome, aluminum and a sheelitovy concentrate, in a covering forms the strengthening phase ‒ intermetallic compound Ni3(AlTi). Possible mechanisms of hardening of blankets of metal products at electrospark modifying are considered, and also results of a research of influence of the gas interelectrode environment on covering thickness, density of defects of a crystal structure of materials and tribological properties of the modified blankets and coverings. Use of technology of electrospark processing promotes manifestation of a complex of mechanisms of hardening from which dominating are dispersive hardening coherent particles of carbides and intermetallic compound, and also a strongly solution alloying. The received results demonstrate active participation of the gas environment in change of physicomechanical and tribological properties of coverings and blankets. So, at electrospark processing in the atmosphere of oxygen the minimum thickness of a covering (about 30 μm) and the maximum wear resistance is recorded. It is connected with the fact that crystalline state of the surfaces received in the oxygen-containing environment is characterized by the increased density of dislocations. Besides, according to the X-ray phase analysis, under a microdimensional covering the disperse strengthened blanket with formation of intermetallic compound settles down that also promotes increase in extent of hardening of a steel surface. It is shown that the reasonable choice of a ratio of the mechanisms of hardening operating when processing with electrospark modifying allows to provide a necessary complex of physicomechanical and tribological properties of the formed coverings.

High-energy metal surfaces processing by electrospark modification (ESM) leads to formation of the difficult structural state of work materials in non-equilibrium thermodynamic conditions by the self-organizing laws. The article deals with the fractal geometry approaches for a quantitative assessment of the erosion processes by using ESM and the surface structure states after treatment. The authors determine the synergies between fractal dimensions of the surface structures, received by ESM of steel, and their physical and mechanical properties. They point out the surface formation with the maximal gauge, microhardness and durability in the case of definite energy of a spark impulse. In this condition, the fractal dimension of structures is maximum too.