Sergei Tarasov

Russian Academy of Sciences | RAS · Institute of Strength Physics and Materials Science of the Siberian Branch

Surface temperature is among crucial factors which control wear during sliding dry contact. Using computer modeling, we study the possibility to achieve close to zero rate of surface wear during sliding friction of the special type of materials which possess negative thermal expansion. The numerical simulations reveal two wear regimes for materials...

Interaction between nickel base superalloy ZhS6U used as a friction processing tool for in-situ synthesis of intermetallics in Ti6Al4V and this titanium alloy metal has been studied. Severe abrasion-adhesion wear was localized on the tool’ pin areas while shoulder was protected by mechanically mixed layer. Generation of titanium enriched mechanical...

Electron beam additive manufacturing with simultaneously controlled feeding and melting of ER321 stainless steel and CuA19Mn2 bronze wires was carried out. The composite microstructure was formed consisting of homogeneously distributed ferrite and nickel-enriched bronze grains. Intensive intermixing and diffusion in the melted pool caused redistrib...

In the presented work, the effect of friction stir processing admixing the zirconium tungstate ZrW2O8 powder on the microstructure, mechanical and tribological properties of the AA5056 Al-Mg alloy stir zone has been studied. The FSP resulted in obtaining dense composite stir zones where α-ZrW2O8 underwent the following changes: (i) high-temperature...

For the first time additively manufactured aluminum bronze containing stabilized β′ -phase was annealed at 400–800 ◦C. Thermal decomposition into solid solutions started at 400 ◦C with precipitation of the Al-rich one on the surface. The intensity of β′ -phase decomposition enhanced with the annealing temperature in the range 400–675 ◦C which, howe...

Computer modeling of rubbing between two surfaces with microasperities capable of expanding or contracting under conditions of frictional heating (i.e., possessing either positive and negative coefficient of thermal expansion (CTE)) allowed for the identification of wear-and-friction regimes on model ceramic materials. Assuming that no adhesion was...

We study the mechanism of formation of the multilayer structure of the subsurface regions of WC/Mn13 steel cermets after sliding on a steel disk at speeds from 10 to 37 m/s and contact pressure of 5 MPa in order to elucidate the fundamental role of the processes of tribooxidation on a worn surface in the formation of the tribomechanical properties...

Lap-welded joints between Ti-6Al-4V and Al-4Cu-1Mg were obtained using water-cooling-bath friction stir welding at different FSW tool rotation rates. The increase in the tool rotation rate from 350 to 375 RPM leads to better plasticization of the titanium alloy, elimination of stir zone defects, better interlocking and bonding with the aluminum all...

The effects of heat input magnitude and adjustment on microstructure and mechanical characteristics of Al-5 %Si and Al-12 %Si alloys prepared using electron beam wire feed (EBAM) and wire-arc additive manufacturing (WAAM) have been investigated. The effect of aging under cyclic reheating the previously deposited layers has been revealed as depended...

Electron beam additive manufacturing from dissimilar metal wires was used to intermix 5, 10 and 15 vol.% of Ti-Al-Mo-Zr-V titanium alloy with CuAl9Mn2 bronze on a stainless steel substrate. The resulting alloys were subjected to investigations into their microstructural, phase and mechanical characteristics. It was shown that different microstructu...

Earlier studies have shown that it is possible to successfully obtain Ti6Al4V-Cu alloys with various copper concentrations using the double-wire electron beam additive manufacturing. Obtaining these alloys is of a practical interest for creating a titanium-base composite material with reduced risk of spontaneous combustion, which could be used in f...

Electron beam additive manufacturing with simultaneous feeding of two dissimilar metal wires was used to obtain Ti-6Al-4V specimens successively alloyed with 0.6, 1.6, 6.0 and 9.7 wt % Cu. The specimens were characterized for microstructure, phases, and mechanical properties. Increasing the copper content in the alloy from 0.6 to 9.7 wt % resulted...

The authors investigated the microstructure, phase composition and mechanical properties of the steel-bronze composite obtained by electron beam additive manufacturing with simultaneous supply of aluminum bronze wires BrAMc9-2 and stainless steel 06Kh18N9T. X-ray diffraction analysis revealed that the composite contains 25 % (vol.) of aluminum bron...

Various industries are widely using the austenitic stainless steels, and these steels possess the potential to improve their mechanical properties through alloying and deformation machining. However, such material improvement could also affect the quality of its machine cutting. The paper studies the influence of intensive plastic deformation on st...

The use of interlayer impact treatment for structural modification and improvement of mechanical characteristics of EBAM CuAl7 bronze samples is investigated using optical microscopy and tensile testing. It has been established that the structural state of the EBAM impact treated samples is determined by such parameters as the impact energy and thi...

The authors investigated the features of structural-phase state of a composite based on stainless austenitic steel with addition of 25% (vol.) aluminum bronze. The composite was obtained by electron beam additive technology with simultaneous feeding of two wires. The paper considers analysis of the structural-phase state and mechanical characterist...

This paper is devoted to using multi-pass friction stir processing (FSP) for admixing 1.5 to 30 vol.% copper powders into an AA5056 matrix for the in situ fabrication of a composite alloy reinforced by Al-Cu intermetallic compounds (IMC). Macrostructurally inhomogeneous stir zones have been obtained after the first FSP passes, the homogeneity of wh...

: In the present work, the tribological experiments on sliding the electron beam composite M2+WC coating have been carried out with characterization of the sample microstructures and phases both before and after the testing using metallography, SEM, EDS, and XRD. The sliding in the speed range 0.8–3.6 m/s resulted in simultaneous reduction in both...

A novel approach to electric explosion of intertwined wires to obtain homogeneous powder mixtures intended for preparing feedstock for extrusion 3D printing has been applied. The powder were composed of spherical micron-and nano-sized W/Cu particles in-situ alloyed by Zn and Ni during electric explosion of intertwined dissimilar metal wires is offe...

In this study, the two-dimensional digital image correlation (DIC) technique has been applied to sequences of images taken from the surfaces of porous, segmented alumina samples during uniaxial compression tests. The sintered alumina was structurally composed of polycrystalline alumina grains with interior ~3–5-µm pores, a network of discontinuitie...

Electron beam additive manufacturing with simultaneous feeding of two dissimilar metal wires was used to obtain Ti-6Al-4V samples successively alloyed with 0.6, 1.6, 6.0, and 9.7 wt % Cu. The samples were characterized for microstructure, phases, and mechanical properties. Increasing the copper content in the alloy from 0.6 to 9.7 wt % resulted in...

The authors investigated tribological characteristics, phase composition of friction surfaces and microhardness of near-surface regions of WC–(Fe–Mn–C) composites with a two-phase (γ + α′) matrix containing 4 % wt. Mn (WC – 80G4), and a single-phase matrix of γ-iron containing 20 % wt. Mn (WC – 80G20) after friction on a disk of high-speed steel at...

In this work, we studied single-layer ZrN and CrN coatings, as well as multi-layer ZrN/CrN coatings deposited by the vacuum-arc method on WC-8 wt.% Co substrates. The sliding friction parameters were preset to simulate different operating conditions for coatings, i.e., severe and zero wear regimes. During the tests, the friction coefficient, acoust...

Friction stir welding (FSW) of titanium alloy was carried out using liquid cooling of the FSW tool made of heat-resistant nickel superalloy. Cooling of the nickel superalloy tool was performed by means of circulating water inside the tool. The FSW joints were characterized by micro-structures and mechanical strength. The mechanical strength of the...

The authors investigated tribological characteristics, phase composition of worn surfaces and microhardness of subsurface regions of WC-(Fe-Mn-C) composites with a two-phase (γ + α′) matrix containing 4 wt % Mn (WC-80G4), and a single-phase matrix of γ-iron containing 20 wt % Mn (WC-80G20) after sliding against a disk of high-speed steel at a conta...

The authors investigated the features of structural-phase state of a composite based on stainless austenitic steel with addition of 25 % (vol.) aluminum bronze. The composite was obtained by electron beam additive technology with simultaneous feeding of two wires. The paper considers analysis of the structural-phase state and mechanical characteris...

Multilayer nitride coatings provide some of the best performance when in their use for the production of metalworking tools. In this work, vacuum-arc plasma-assisted deposited multilayer ZrN/CrN coatings with different numbers of constituent layers were characterized for high-temperature oxidization in air using weighing, confocal and scanning elec...

Novel composite CuA19Mn2/Udimet-500 alloy walls with different content of the Udimet 500 were built using electron-beam double-wire-feed additive manufacturing. Intermixing both metals within the melted pool resulted in dissolving nickel and forcing out the aluminum from bronze. The resulting phases were NiAl particles and grains, M23C6/NiAl core/s...

Elastoplastic properties of tribological layers generated on WC–(Fe–Mn–C) composites with matrices composed of γ-iron containing 20 wt % Mn (WC–80G20) and of γ + α' with 4 wt % Mn (WC– 80G4) after sliding against a high-speed steel disk at contact pressure of 5 MPa and sliding speeds in the range from 10 to 37 m/s have been investigated. It was est...

Microstructure and mechanical characteristics of aluminum bronze fabricated using electron beam additive manufacturing (EBAM) under adjusting the heat input as a function of the sample's height are investigated. It is shown that this adjustment has an effect on the dendrite grain size, morphology and mechanical characteristics. Columnar high aspect...

WC/Y–TZP–Al2O3 hybrid ceramic–matrix composites (CMCs) with dispersed Hadfield steel particles were sintered and then tested at sliding speeds in the range of 7–37 m/s and contact pressure 5 MPa. Fast and low-temperature sinter-forging allowed obtaining micron-sized WC grains, submicron-sized alumina-reinforced yttria partially stabilized polycryst...

Microstructure and mechanical characteristics of aluminum bronze fabricated using electron beam additive manufacturing (EBAM) under adjusting the heat input as a function of the sample’s height have been investigated. It was shown that such an adjustment of the heat input had effect on the dendrite grain size and morphology as well as mechanical ch...

WC-(Fe-Mn-C) composites with γ-iron and γ + α' matrices were sintered and then tested at sliding speeds in the range 7-37 m/s. The coefficient of friction was exponentially reduced as a function of sliding speed reaching its minimum at 37 m/s. This behavior was provided by the mechanochemical formation of iron tungstate FeWO4 on the worn surfaces o...

Electron beam additive wire-feed manufacturing of Cu-3wt.%S-0.8wt.%Mn bronze thin wall on a stainless steel substrate has been carried out at heat input levels of 0.19, 0.25, and 0.31 kJ/mm. The microstructures of as-deposited metal ranged from low aspect ratio columnar with equiaxed grain layers to zig-zagged and high aspect ratio columnar, as dep...

The paper shows the regularities of plastic deformation and fragmentation of pure copper single-crystal after friction stir welding. The obtained data indicate a high role of deformation bands formation with changed orientation of crystal lattice along the contour of the stir zone. Near the stir zone, a larger number of deformation bands are also i...

Multi-pass friction stir processing (FSP) was used to obtain a titanium alloy/copper hybrid composite layer by intermixing copper powder with a Ti6Al4V alloy. A macrostructurally inhomo-geneous stir zone was obtained with both its top and middle parts composed of fine dynamically recrystallized α-and -Ti grains, as well as coarse intermetallic com...

Novel mixtures of micro- and nanoparticles have been obtained by simultaneous electrical explosion of three intertwisted wires (EEW). The possibility of obtaining of titanium‑aluminum micro- and nanoparticles alloyed with molybdenum, tungsten and copper by the electrical explosion of Ti/Al/(Mo, W, Cu – up to 6 at. %) wires has been shown. Spherical...

Nanostructured W-31wt.%Cu composite was for the first time produced via magnetic pulse compaction from bimetallic particles obtained using electric explosion of intertwisted copper/tungsten wires in argon and then characterized for microstructures, mechanical strength and tribological behavior at high temperatures. Microstructure of the composite i...

AA5154 aluminum alloy wall was built using EBAM where the wall’s top layers were alloyed by depositing and then remelting a Mo powder-bed with simultaneous transfer of aluminum alloy from the AA5154 wire. The powder-beds with different concentrations ofMo such as 0.3, 0.6, 0.9 and 1.2 g/layer were used to obtain composite AA5154/Mo samples. All sam...

In this work, the authors studied the elastoplastic properties of the formed tribological layers of WC – (Fe – Mn – C) composites with matrices consisting of γ-iron (containing 20 % Mn (WC – 80G20)) and γ + α′ (containing 4 % Mn (WC – 80G4)) after friction on a high-speed steel disk at contact pressure of 5 MPa and sliding speeds in the range from...

Electron beam additive wire-feed deposition of Cu-7.5wt.%Al bronze on a stainless-steel substrate has been carried out at heat input levels 0.21, 0.255, and 0.3 kJ/mm. The microstructures formed at 0.21 kJ/mm were characterized by the presence of both zigzagged columnar and small equiaxed grains with 10% of Σ3 annealing twin grain boundaries. No eq...

A gradient transition zone was obtained using electron beam deposition from AA4047 wire on AA7075 substrate and characterized for microstructures, tensile strength and corrosion resistance. The microstructure of the transition zone was composed of aluminum alloy grains, Al/Si eutectics and Fe-rich and Si-rich particles. Such a microstructure provid...

Dissimilar friction stir processing on CuZn37/AA5056 was performed to study structural and phase evolution of a friction stir zone. Formation of 5-10 μm intermetallic compounds (IMCs) such as Al2Cu was the main type of diffusion reaction between copper and aluminum. Other alloy-ing elements such as Mg and Zn were forced out of the forming Al2Cu gra...

High-speed continuous sliding experiments on ZrB2-20 vol% SiC ultra-high temperature ceramics have been carried out to elucidate specifics and details of tribooxidation under conditions of subsurface deformation and friction generated heating. Subsurface multilayer structure layer phase composition was obtained to testify on the intense mass transf...

Evaporation of paraffin and ultra-high-molecular-weight polyethylene admixed with alu-mina powder for the slip casting and sintering process allowed the obtainment of segmented porous alumina ceramics with 50% total porosity, whose deformation behavior we studied. Structurally, these ceramic materials were composed of large and small pores, and a s...

The paper studies the structure and mechanical properties of the copper alloy based on a Cu–Al–Si–Mn system, produced by wire-feed electron-beam additive manufacturing (EBAM). Energy dispersive X-ray spectroscopy on the scanning electron microscope is carried out to investigate the microstructure and composition of the obtained copper alloy specime...

The research was devoted to studying unlubricated tribological behaviors of γ-TiAl-based coatings in the temperature range 25–400 °C. These γ-TiAl-based intermetallic coatings alloyed with Fe or Mn were formed on CP-Ti workpieces using a non-vacuum electron beam deposition. The microstructure, phase and elemental analyses proved the formation of γ-...