The effect of the regime of electrospark alloying (ESA) on the thickness, hardness, and phase composition of the alloyed hardened layer on the surface of specimens of titanium alloy VT1-0 is studied. The thickness of the layer depends considerably on the parameters of the ESA process, and the hardness level is determined by the phase composition.

Correlation between the ultimate tensile strength and the hardness of aluminum alloy 2219 and its joints welded with a variable-polarity tungsten electrode in inert gases (VPTIG) and by friction stir welding (FSW) is studied. The yield strength (σy) and the ultimate strength (σr) of the base metal, the microhardness and the strain hardening coefficient of the welded joints are determined. Linear correlation

We present the results of metallographic investigations of the structure and microhardness and the results of the bench tests of the threads of tubings made of steels of the strength class D after finishing electromechanical surface quenching in pairs with commercial couplings.

Medium-alloy chromium-nickel cast iron with different contents of silicon and vanadium is studied. The composition of the carbide phase, the distribution of elements in the carbide phase and in the metallic matrix, and the proportion of the structural components and of the carbides are determined. The effect of the form of globular graphite on the mechanical properties of the cast iron is described

The structure of retained austenite in wear-resistant steels 150KhNML and Kh12MFL of pearlitic and ledeburitic classes is studied under the conditions of abrasive wear after different variants of heat treatment. The working surfaces of the steels are subjected to electron microscope transmission analysis. It is shown that the retained austenite formed as a result of high-temperature quenching (1100

The structure, the hardness, and the thickness of the hardened surface layer of normalized steel 45 are studied after electromechanical treatment (EMT) with dynamic application of the forming force. The effect of the density of the current of the pulsed EMT on the structure, the microhardness and the thickness of the hardened surface layer is determined. The properties of the hardened layer of the

Steel AISI4140 is studied after plasma nitriding and preliminary oxidation. The structure of the preliminarily oxidized surfaces after the nitriding is studied by scanning electron microscopy (SEM). The free surface energy is computed from the results of the measurement of the angle of contact between a liquid drop and the surface studied. The thickness of the nitrided layer is determined. The phase

The effect of ion nitriding in glow discharge on the structure and mechanical properties of steel R6M5 after quenching from 1200°C and tempering at 560°C with preliminary severe plastic deformation (SPD) is studied. Application of ion nitriding in glow discharge is shown to be effective for hardening the high-speed steel RM5 after SPD.

The microstructure and mechanical properties of maraging steel 350 is studied after aging at 500 – 650°C. The yield strength, the ultimate strength, the impact energy, and the hardness of the steel are determined. The volume fraction of reverted austenite after the aging is assessed. The impact energy, the elongation, and the product of the ultimate strength by the elongation are shown to depend on

Processes of formation of structure and properties in the functional layer from chromium-nickel cast iron of two-layer centrifugally cast indefinite forming rolls under crystallization and subsequent tempering are investigated. The temperatures of the start and finish of the phase transformations, the phase composition, and the contents of martensite and retained austenite in the material of the functional

The structure of a coating based on a mixture of particles of Cu and Zn deposited by the method of gas dynamic spraying is studied. An x-ray diffraction analysis and a microscopic spectrum analysis are used to determine the structure and the elemental composition of the coating. Development of diffusion after the formation of the coating is shown to yield a solid solution of copper and zinc in it.

Mg – HA (magnesium-hydroxyapatite) composites obtained by powder metallurgy and subjected to sintering at three different temperatures and subsequent hot extrusion for making orthopedic implants are studied. The relative density, the hardness and the properties after tensile and impact tests are determined with the use of optical and scanning electron microscopy.

Titanium carbosilicide is synthesized by the method of spark plasma sintering (SPS) from a powder mixture of plain elements (Ti, Si, C). The stages of the synthesis process are considered, i.e., pressing of the powder mixture, melting of the constituents, chemical reactions, and phase transformations. The materials synthesized at 1000, 1300, 1500 and 1600°C are studied by the methods of phase, diffraction

Sparingly alloyed high-manganese austenitic steels 40G20 and 25G20S3 are studied. The phase composition, the structure and the mechanical properties of the steels are determined after quenching from the austenitic range, and their variation during tension of standard specimens is studied by the methods of transmission electron microscopy and x-ray diffraction analysis. The characteristics of strain

Amorphous alloys Fe81Zr5Nb4B10 and Fe40.5Co40.5Zr5Nb4B10 obtained by melt spinning and subjected to annealing at different temperatures are studied. The activation energy of crystallization of the alloys is determined for different heating rates. It is shown that the primary product of crystallization of amorphous alloy Fe81Zr5Nb4B10 is an α-Fe phase and a phase with a structure of type α-Mn. In the

RGO/Cu – Zr – La alloy produced by repeated pressing and sintering is studied. The effect of the reduced graphene oxide (RGO), Zr and La components on the microstructure, mechanical properties, conductivity, and oxidation resistance of the alloy is studied. It is shown that precipitation of RGO and Zr on grain boundaries hinders displacement of the grain boundaries. The mechanical characteristics of

The microstructure and the wear resistance of precision nickel alloy 40KhNYu-VI used for the production of paramagnetic bearings are studied after glow discharge nitriding. It is shown that the continuous layer of CrN nitride formed under the nitriding provides substantial elevation of the wear resistance of the surface of the parts. The wear intensity after the nitriding decreases by a factor of 5

The effect of artificial aging on the mechanical properties of Al6082 alloy and Al6082/(2 – 10%)Al2O3 composite produced by stir casting is studied. The structure is studied with the help of a field emission scanning electron microscope (FESEM). The stress-strain curves, the impact energy and the hardness are measured. It is shown that growth in the fraction of the hardening phase and artificial aging

Tough-pitch copper M1 is studied after deformation by the method of equal channel angular pressing (ECAP) in a die with parallel channels with the use of cryogenic cooling in liquid nitrogen. Comparative analysis of the properties of the copper after the ECAP with cooling in liquid nitrogen and at room temperature is performed. Special features of formation of ultrafine-grained structure in quenched

The properties of steel parts after carburizing in low-pressure acetylene are studied. The thickness of the carburized layer, its hardness, the microstructure, and the hardness of the core are determined after carburizing at 900 – 960°C with simultaneous shortening of the process from 104 to 44 min. The data obtained for the diffusion of carbon make it possible to predict the profiles of carbon distribution

The effect of annealing and SiC additions on the process of wear of electrolytic nickel-phosphorus (NiP) coatings under different friction conditions (sliding, fretting and fretting-corrosion) is studied. It is shown that the sliding friction causes much lower wear than the fretting wear and the fretting corrosion. The lowest wear under the friction conditions considered is exhibited by the heat treated

We carried out structural and tribological investigations of steels and alloys after different modes of their nitriding. On the basis of the results of tribological tests and metal-physics investigations, we estimated the efficiency of each applied procedure of treatment and determined the characteristics of the structural state of nitrided layer, promoting the improvement of the wear resistance of

Optical and electron microscopy, x-ray spectral microanalysis, and thermogravimetric analysis in combination with differential scanning calorimetry are used to study the high-temperature oxidation behavior of alloy HP40NbTi of the Fe – 25Cr – 35Ni system prepared by static and centrifugal casting, and also oxidation process kinetics. It is shown that high-temperature oxidation of refractory alloy HP40NbTi

Behavior of promising aluminum-base composite materials reinforced with silicon carbide particles and discrete alumina fibers is analyzed under impact loading conditions. Workpieces for test specimens are prepared by liquid-phase combination of the components. Results of impact bending tests and analysis of fracture surfaces are used to determine the effect of fillers on material impact behavior and

Results are provided for studying deformation methods of steel surface nanostructuring and hardening with martensitic, pearlitic and austenitic structures. A new method of ultrasonic impact-friction treatment is considered. Combined methods of nanostructuring treatment (friction treatment + annealing) are proposed for a metastable Cr – Ni steel. The possibility is demonstrated of activating steel saturation

Mechanical properties, phase composition, and structure of test melts of high-strength pseudo-β-titanium alloyed with yttrium and gadolinium are studied. Special features of the morphology of REM oxide particles and their distribution within the alloy structure are considered. Quantitative metallographic analysis of the structural components is conducted. Sizes of primary β-grains, volume fraction

The effect of deforming cutting (DC) on structural and phase transformations in iron and steels 35 and U8 is studied with the help of scanning optical and transmission electron microscopy. It is shown that with an increase in carbon content test material structure and phase composition become more complex.

Copper–fullerene/fullerene soot composites are prepared using different processes. Structure, hardness, tribological properties, and thermal conductivity of the composites are studied. It is shown that mixing at the molecular level makes it possible to obtain copper–fullerene/fullerene soot composites with more uniform carbon distribution and better combination of properties than mechanical mixing

Results are provided for studying deformation methods of steel surface nanostructuring and hardening with martensitic, pearlitic and austenitic structures. A new method of ultrasonic impact-friction treatment is considered. Combined methods of nanostructuring treatment (friction treatment + annealing) are proposed for a metastable Cr – Ni steel. The possibility is demonstrated of activating steel saturation

We propose an atomistic description of polymorphic transformations in metal alloys, according to which an elementary act of transformation is reduced to the transfer of diagonals of a rhombus formed by two triangles. Metallic atoms are located in the corners of these triangles, and their common edge is transferred (i.e., turns into the long diagonal of rhombus). We estimated the energy barrier of polymorphic

The structures and phase compositions of highly-alloyed corrosion-resistant cast irons ChKh22 and ChKh20M, and also stainless steels 10Kh24N19G2M (austenitic) and 20Kh28N8AM3D3S (austenitic-ferritic) are studied by optical and scanning electron microscopy, x-ray diffraction analysis, and hardness measurement. Variation of the phase composition during steel crystallization is analyzed. Corrosion behavior

To the article “Structural Features and Application Prospects for High-Nitrogen Austenitic Steels,” by O. A. Bannykh, Vol. 61, Nos. 5 – 6, pp. 287 – 294, September, 2019.

Processes of intermetallic phase formation in functional coatings prepared by cold gas-dynamic spraying of Ni – Al, Ni – Ti – Al, Ti – Al, and Ni – Ti powder mixtures are studied. On heating of the coatings containing Al, the main phase transformations proceed in the range of 450 – 750°C, and phase formation processes in the coatings based on the Ni – Al and Ni – Ti – Al systems develop in a similar

Single crystals of (1 – x)TlGaSe2 ∙ xDy (x = 0; 0.01; 0.03) were synthesized. The laws of variation of the dielectric parameters and conductivity of (1 – x)TlGaSe2 ∙ xDy materials are determined as a function of their composition and frequency of the ac electric field. Doping of dysprosium into TlGaSe2 crystal matrix substantially increases the real and imaginary components of the complex dielectric

Ductility of chromium steels 15Kh13N2, 10Kh13N3MFB, and 10Kh17N13M2T is studied as a function of the stress-strain state and deformation temperature using fracture phenomenological theory. Computer simulation of the process of pipe extrusion is performed using QForm software. A dependence is proposed describing the ductility diagram, and empirical coefficients are determined by tests in a Gleeble 3800

The effect on optical properties of modifying KO-921 organosilicon compound with Al2O3 nanoparticles in the concentration range of 0.5 – 7 wt.% after irradiation with electrons is studied. Optimum values of nanoparticle concentration in order to improve compound radiation properties are established.

A new method for improving ferritic-pearlitic steel brittle fracture resistance is considered. The favorable effect of thermal improvement and subsequent programmed strengthening hardening during additional medium-temperature tempering is demonstrated on the example of steel 09G2S. The new technology makes it possible to lower the steel 09G2S critical brittleness temperature Tc0 determined in terms

Preparation of nitrogen-containing steel 04Kh20N6G11M2AFB powder and subsequent selective laser melting (SLM) are studied. The effect of oxygen in the atomizing nitrogen gas on powder nitrogen content is established. Nitrogen content in a monolithic sample is maintained after SLM. Comparative analysis of SLM-specimen mechanical properties and 04Kh20N6G11M2AFB steel is conducted.

A possibility of using hardening treatment of the stamping tools in high-pressure nitrogen with thermal cycling was analyzed. A thermal field of Kh12MF steel batches under accelerated heating and cooling conditions during thermal cycling was studied. A satisfactory agreement between the experimental and prescribed temperature conditions in the central and peripheral batch regions has been established

Optical and electron microscopy and x-ray spectral microanalysis are used to study the transformation of the phases present in the structure of cast refractory alloy HP40NbTi during prolonged high-temperature oxidation. It is established that during oxidation alloy phase chemical composition changes continuously and by complex laws in relation to the surroundings, temperature, and exposure duration

The main directions of the development of additive technologies at the Peter the Great St. Petersburg Polytechnic University are considered. Fabrication and research of spherical powders of complexly alloyed alloys for additive production from metal waste and of functionally graded materials with variable structure, chemical composition and porosity, synthesis of intermetallic titanium alloys by selective

The size and volume fraction of fine particles of secondary β -phase formed during hardening heat treatment of pseudo-β-titanium alloy VT22 are determined using low-angle scattering of neutrons, x-ray diffractometry, electron back-scatter diffraction, and transmission microscopy combined with x-ray spectral microanalysis. Based on comprehensive use of experimental data obtained by methods of different

The paper discusses the application potential of quenching in high-pressure nitrogen with respect to mediumand high-alloy steels, as well as precipitation-hardening alloys. A procedure for predicting the structure and properties of steels and alloys after quenching is proposed. It is shown that gas quenching provides a high level of mechanical properties while maintaining the geometry of the precision

The results of creep tests in the bending mode at 1150 – 1200°C for the Nb – Si – X alloy (X = Mo, Ti, Hf, Zr, Cr, Al) after hot isostatic pressing and after induction melting in the mode of directed crystallization are analyzed. It was shown that the creep rate of powder alloys is an order of magnitude higher than the creep rate of an alloy with a directed structure, which is related to the microstructural

Systematic analysis of the state and prospects of the development of additive technologies for computer-aided production is conducted to show a new paradigm of their evolution. An approach determining the additive methods as synergy technologies that provide self-organization of surface phenomena is suggested. The new approach is used for choosing the most efficient energy sources and materials for

Diffusion of boron in FeB and Fe2B layers under solid boriding of steel AISI D2 (the Russian counterpart is Kh12MF) is simulated. Two approaches are used to assess the diffusion coefficients in solid-phase boriding, i.e., the concept of the mean value of diffusion coefficient in the FeB – Fe2B system and consideration of the growth kinetics of each of the two boride layers with the use of a system

Vanadium carbide coatings deposited on steel AISI 52100 (the Russian counterpart is bearing steel ShKh15) by the method of thermo-reactive diffusion (TRD) in a sealed container at 900°C for 2 – 8 h are studied. The structure of the coatings is analyzed by scanning electron microscopy and x-ray diffractometry. The microhardness is measured. Adhesion tests are performed by the Daimler-Benz Rockwell-C

Friction treatment (FT) with a sliding indenter forming nano- and submicrocrystalline austenite structures in the surface layer of austenitic steel 03Kh1N14M3T (the volume fraction of strain martensite does not exceed 1.5%) is studied. It is shown that the FT hardens the surface of the steel to 720 HV0.025 and raises the wear resistance under the conditions of sliding friction with a lubricant by a

The structure and the hardness of hybrid metal matrix composites with a matrix from alloy 6063 of the Al – Mg – Si system and dispersoid particles of Al2O3 and SiC are studied. At less than 5 wt.% dispersoid in the composition the distribution of particles in the matrix is uniform; at a higher content of dispersoid the particles are segregated even over grain boundaries of the matrix. The density and

The effect of the relative fraction of powder of steel 4605 (0.42% C, 2.15% Ni, 0.49% Mo, 0.1% Si) mixed with a polymer binder in injection molding of billets (the MIM technology) on their tensile mechanical properties, hardness, density and toughness is studied. The polymer binder is based on high-pressure polyethylene (HDPE), paraffin wax (PW) and stearic acid (SA). It is shown that the mechanical

The possibility of fabrication of permanent magnets based on a Fe – Cr – Co alloy with reduced cobalt content by the MIM technology is considered. The method is used to obtain permanent magnets 3 × 2 × 6 mm in size with magnetic properties close to those of standard 25Kh15KA magnets produced by investment casting. The microstructure and the magnetic properties of the alloys are studied.

The methods of optical and scanning electron microscopy and x-ray spectrum microanalysis are used to study and to compare the special features of formation of metastable trialuminides under rapid crystallization of superheated melts of the Al – Hf – Sc and Al – Hf – Ti systems. Heating of such melts by over 100°C above the liquidus temperature yields Aln(Hf1–xScx) and Aln(Hf1–x Tix) aluminides with

X-ray diffractometry and mathematical processing of diffraction patterns by the A. N. Tikhonov regularization method, which enhances the resolution, are used to study the kinetics of formation of phases in the forward reaction of the HDDR process in its early stages (the first minutes) in alloys based on Nd – Fe – Co – B – Zr.

The effect of nickel content in a high-strength medium-carbon complexly alloyed steel on the structural and phase transformations, location of critical points, quantitative parameters of microstructure and critical quenching rate is studied. Thermokinetic diagrams of decomposition of supercooled austenite in the steel with original composition are plotted and the characteristic types of microstructure

The structure and mechanical properties of different-thickness copper foils obtained by chemical and electrochemical deposition at high and low temperatures are studied. The activation energy and the driving force of the recrystallization are determined.

Results of a study of the low-cycle fatigue of singe crystals with orientations 〈001〉 and 〈111〉 from rhenium-containing refractory nickel alloy ZhS32 and of specimens of alloy ZhS32 obtained by selective laser melting on a single-crystal substrate from alloy ZhS32 at “soft” loading cycles (the controlled parameter is the strength amplitude in a cycle) at 750°C and “rigid” loading cycles (the controlled

Abrief review of reported data on special features of formation of structure in surface layers of metallic materials under contact deformation in active lubricants is presented. The factors affecting the kinetics of the process of formation of a wear resistant structure are considered.

The behavior of the structure of abrasion-resistant alloys of the Fe – Cr – C – Mo – Ni – Ti – B system during electric arc cladding with introduction of ultrafine particles of titanium nitride into the welding pool in the composition of both the electrode and the filling powder wires is considered. The effect of titanium nitride on the hardness and wear resistance of the experimental clad alloys at

The effect of nickel additions on the microstructure and ultimate tensile strength of alloy Al – 10% Si – 5% Cu in cast and heat treated conditions is studied. The nickel content optimum for obtaining a maximum-strength alloy is determined. The conditions at which a fishbone morphology negatively affecting the mechanical properties does not form are determined. Mechanical stirring of the melt before

The temperatures of appearance and degradation of short-range and long-range ordering in VDM® Alloy C-4 (UNS 2.4610/N06455) are determined with the help of physical methods of research. The sensitivity of the methods to these effects is studied. The results obtained are used to make recommendations on determination of the temperatures of disordering-ordering and ordering-disordering transitions in