Victor P. Sergeev

Fatigue life enhancement by irradiation of 12Cr1MoV steel with a Zr+ ion beam. Mesoscale deformation and fracture

The structure and properties of 12Cr1MoV steel irradiated with a zirconium ion beam were studied by optical microscopy, scanning electron microscopy, and micro- and nanoindentation. It is shown that the modification covers the entire cross-section of the irradiated specimens to a depth of 1 mm. The data on irradiation-induced structural changes are used to interpret the changes in mechanical properties of the irradiated specimens under static and cyclic loading. Particular attention is given to analysis of strain estimation by the digital image correlation method.

Investigation of the structural-phase state and the impact-protective properties of optically transparent Si-Al-N coatings

The results of the study of the structural-phase state, the optical and impact-protective properties of Si-Al-N coatings with a thickness from 0.9 to 6.2 μm deposited by pulsed magnetron sputtering on a substrate made of the KV type quartz glass are presented. The formation of the nanoscale single-phase AlN (hcp) with a crystallite size up to 20 nm was discovered by the X-ray diffraction method. Coatings based on Si-Al-N are characterized by high values of microhardness (Hμ ≈ 25 GPa) and the coefficient of elastic recovery (ky = 0.71–0.85). The Si-Al-N coatings are characterized by a high degree of transparency (about 80%) in the visible range of wavelengths and are completely opaque in the ultra-violet regions. The refractive index of the glass samples with coatings on the basis of Si-Al-N was determined using the transmission spectra whose value decreases from 2.04 to 1.87 with increasing thickness of coatings. The results of the study of the surface density of the craters formed on the surface of the initial quartz glass and the quartz glass with Si-Al-N coatings due to the influence of high-speed Fe particles of the micron size are described.The results of the study of the structural-phase state, the optical and impact-protective properties of Si-Al-N coatings with a thickness from 0.9 to 6.2 μm deposited by pulsed magnetron sputtering on a substrate made of the KV type quartz glass are presented. The formation of the nanoscale single-phase AlN (hcp) with a crystallite size up to 20 nm was discovered by the X-ray diffraction method. Coatings based on Si-Al-N are characterized by high values of microhardness (Hμ ≈ 25 GPa) and the coefficient of elastic recovery (ky = 0.71–0.85). The Si-Al-N coatings are characterized by a high degree of transparency (about 80%) in the visible range of wavelengths and are completely opaque in the ultra-violet regions. The refractive index of the glass samples with coatings on the basis of Si-Al-N was determined using the transmission spectra whose value decreases from 2.04 to 1.87 with increasing thickness of coatings. The results of the study of the surface density of the craters formed on the surface of the i...

Internal stresses and structure of multilayer coatings on the basis of Zr-Y-O / Si-Al-N

X-ray and TEM research of the structure of multilayered coatings consisting of the alternating layers Si-Al-N and Zr-Y-O of equal thickness are carried out. It is shown that the boundaries between different layers are sharp enough, and the chemical composition in each layer is homogeneous. The phase composition of the layers on the basis of Zr-Y-O contains basically nanocrystalline ZrO2 and the layers on the basis of Si-Al-N contain Si3N4 amorphous phase. The internal field of stresses is determined by X-ray and TEM analyses. It is established that the crystal lattice curvaturetorsion and the internal elastic stresses depend on the grain cross-section size of the Zr-Y-O layer.

Magnetron deposition of metal-ceramic protective coatings on glasses of windows of space vehicles

Transparent refractory metal-ceramic nanocomposite coatings with a high coefficient of elastic recovery and microhardness on the basis of Ni/Si-Al-N are formed on a glass substrate by the pulse magnetron deposition method. The structure-phase states were investigated by TEM, SEM. It was established that the first layer consists of Ni nanograins with a fcc crystalline lattice, the second layer is two-phase: 5-10 nm nanocrystallites of the AlN phase with the hcp crystalline lattice in amorphous matrix of the Si3N4 phase.

Influence of intense bombardment of Cu+ ions on microhardness and structure of VT-23 titanium alloy

The structural-phase state of the ion-modified surface layer of the VT-23 titanium samples was investigated by TEM and SEM. The results of the surface modification of the VT-23 titanium alloy by the intense flux of copper ions with energy of 2 keV and the ion current density of 3.5 mA/cm2 were studied. The dependence of the microhardness and the penetration depth of ions as a function of duration of ion treatment was determined. The microhardness was investigated by the nanoindentation method.

Complex research on the interaction of glass with space debris

This paper discusses the interactions of barriers with a spherical impactor and the character of possible deformation and fragmentation of barriers and impactors. The destruction of glass is considered as a process of destruction of fragile material without a part of plastic deformation characteristic of the deformation metals. To calculate the elastic-plastic flow a technique was used which was implemented on the tetrahedral cells and based on the combined use of the Wilkins method for calculating the interior points of the body and the Johnson method for calculating contact interactions. Methods for accelerating the flow of fine particles and the individual spherical particles have been developed. A series of experiments for usual glass and glass with coatings has been carried out.

Phase transformations in nanostructured coatings based on Zr-Y-O and produced by a pulse magnetron sputtering method

Deposition of nanostructured coatings on the basis of Zr-Y-O was implemented by the pulse magnetron methods. Structural-phase states and morphology of the nanostructured coatings were investigated by TEM, SEM and the high-temperature X-ray method. The method of the high-temperature X-ray diffraction revealed the presence of reversible phase transition of the tetragonal phase to the monoclinic phase, which can ensure stress relaxation and closure of surface cracks.

Wear of nitrogen ion implanted copper with tribological Cu-Mo-S coatings

The paper studies the effect of nitrogen ion implantation in copper samples before depositing a solid lubricant Cu-Mo-S coating on their wear resistance during wear testing in pairs with a copper counterface in the argon atmosphere. It was found that wear resistance of samples with Cu-Mo-S coating decreased with the increase in fluence of nitrogen ion implantation.

Microstructure and properties of nanocomposite Al-Si-N system coatings produced by magnetron sputtering

The paper presents the results of investigations of the structural and phase conditions, mechanical and optical properties of Al-Si-N system coating obtained by magnetron sputtering. The thickness of this coating ranges from 3 to 19 µm and is sprayed on silica glass using magnetron sputtering technique. The formation of nanoscale AlN single phase with HCP crystal system and the crystal grain size of up to 20 nm is discovered using the X-ray diffraction method. The texture of [002] orientation is observed in the structure of Al-Si-N-based coatings. These coatings are characterized by high values of microhardness and coefficient of restitution. The transmission spectrum of the coatings are produced within the range of 190-1100 nm. Al-Si-N-based coatings are characterized by a high degree of transparency (≈ 80%) within the visible light spectrum and complete opaqueness in the ultraviolet region. The refractive index and the thickness of Al-Si-N system coating are determined using the transmission spectrum an...

The structure and phase composition of the surface layer of the samples during the processing of VT-10 titanium alloys by copper ions

The phase composition, structure and morphology of the surface of VT-10 titanium modified by copper ions have been investigated by X-ray, SEM and TEM. It has been established that there are intermetallide phases of Cu-Ti equilibrium diagram in the surface layer during the treatment of VT-10 titanium by copper ions. The modified surface layer in the cross section is divided into two layers: up to 1 µm in thickness and from 1µm up to 4.5–5.0 µm, depending on the treatment time. Two-level micro and nanoporous nanocrystalline structure was formed in the modified layer. It was found that the phase structure and the morphology of the surface layers of VT-10 alloys depend on the treatment time.