Activation energy of boron diffusion during pack boriding of armco iron with a constant incubation time for boride formation is estimated using a mean diffusion coefficient model. Experimental verification is accomplished for the model by boriding armco iron at 1253 K for 5 h. Good correspondence is obtained between experimental and calculated Fe2B layer thicknesses.

A comprehensive research was conducted to study long-length (> 10 m), wide (> 2 m), 7 mm thick sheets of high-strength aluminum alloy V95pch after quenching and “softening” aging according to T2 temper conditions. It is shown that a homogeneous (length- and widthwise) structure, typical for such type of semi-finished products made of alloy V95pch, temper T2, can be sustained in wide, long-length sheets

The effect of heat treatment on the microstructure, hardness, and abrasive wear of the hammer mills knives made of steels EN 1.2080, 1.7225, 1.7131, and 1.1191 used in the grain crop processing into groats has been studied. The wear tests were performed using an “impeller-in-cup” type machine, and metallographic studies were performed using optical and scanning electron microscopy. A comparative analysis

Transformations of structure associated with relaxation processes in the inclusion-matrix interphase boundaries of 08Yu, 08Kh18N10T, É3 steels and armco-iron under various external impacts are studied. The possibilities of stress relaxation within the inclusion – matrix boundaries as a result of the emission of dislocations or the splitting of these boundaries are shown. The mechanisms of static, dynamic

The effect of laser treatment parameters for copper cladding applied by explosive welding and subsequent rolling on a titanium surface on coating structure and phase composition is studied. It is shown that the relative (compared with VT1-0 titanium alloy) wear resistance of a coating with an increase in titanium content from 30 to 50% increases at 20°C from 2.9 to 4.4, and at 400°C from 1.7 up to

The wear resistance characteristics of AISI 51B60H and 30MnB5 steels with different carbon and boron contents were investigated. The analysis of the microstructure and hardness of steels was carried out. The specific wear rates in the conditions of dry and wet friction were calculated, and the friction coefficients were determined. The worn surfaces of rail samples were studied by electron microscopy

The effects of primary ferrite on bainitic transformation, microstructure, and properties of low carbon bainitic steel Fe – 0.22C – 2.01Si – 2.20Mn – 0.22Mo are investigated by metallographic and dilatometric methods. It is found that the effect of primary ferrite on subsequent bainite formation appears as a change in the ratio of two competing processes: advance of the austenite–ferrite interface

The treatment conditions yielding steel with a natural ferrite-martensite composite structure are proposed. Structural steels having a banded ferrite-pearlite structure after hot rolling are analyzed. It is shown that the strength achievable by the composite is proportional to the volumetric fraction of the strengthening phase. Based on the experimental data obtained as a result of tension and dynamic

The quality, structure, chemical composition and mechanical properties of bimetallic materials prepared by argon- arc surfacing of copper alloys MNZhKT 5-1-0.2-0.2, Sv-MN18, Sv-MNZhMtsTK 40-1-1-0.3-0.1, MMts40, BrAZhNMts 8.5-4-5-1.5 and Monel NMZhMts 28-2.5-1.5 on high-strength low-alloy steel AB3 are investigated. It is shown that during surfacing copper alloys on steel, high-quality bimetal is provided

We consider specific features of formation of the structure and properties of 03Kh22N5AM3 corrosion-resistant duplex steel in the process of deformation and thermal treatment of rolled milled bars. We analyze the influence of the chemical composition and the conditions of smelting, casting, hot deformation, and heat treatment on the formation of intermetallic phases, which reduce the ductility of the

The kinetics of formation of precipitates in a Cu – 2% Be alloy is studied in terms of the Avrami and Orowan equations.We determine the structure and hardness of the alloy after aging at 260 – 440°C for 0.25 – 10 h and compute the activation energy of precipitates.

The influence of various heat treatment modes (annealing, quenching, tempering) of steel 20 on the carbon dioxide corrosion rate in a 3% NaCl solution in combination with carbon dioxide (CO2) barbotaging was studied. It is established that the quenching followed by high tempering is the most effective heat treatment of steel 20 to achieve a combination of increased mechanical properties and corrosion

The authors have studied grade R260 rail steel after austenization in the temperature range from 800 to 930°C and isothermal soaking at 500, 550, and 600°C followed by quenching in water. The steel structure and abrasive wear resistance were characterized. Recommendations concerning an increase in steel wear resistance were provided.

Steel AISI O2 (type 9G2) for a cold-working tool after different quenching, tempering, and cryogenic treatment regimes is studied. It is established that after cryogenic treatment the amount of residual austenite decreases by a factor of 4.3 compared with a quenched condition. The highest hardness 69 HRC is achieved after quenching and cryogenic treatment, and in this case wear resistance is higher

An experiment is performed for explosive convergence (collapse) of a cylindrical shell of low carbon steel with a ferrite-perlite structure. It is revealed that during ultra-rapid heating caused by high-speed deformation austenite formation occurs in an unusual sequence: first, free ferrite is converted, then pearlite. The decrease in free ferrite transformation temperature is explained by action of

Technology for low-temperature carbonitriding combined with high temperature tempering of cold-worked die steel 6Kh4M2FS (DI55) is proposed. The high efficiency of a paste-like coating based on amorphous carbon and nitrogen-containing components (carbamide and potassium ferricyanide) during die steel cyaniding in the temperature range from 500 to 580°C is demonstrated. The effect of thermochemical

We study the processes and mechanisms of electron-beam melting (EBM) used in the production of high-purity metals. We formulate the requirements that should be imposed on the EBM parameters for the production of high-quality materials and proposed some optimal modes.

Heat resistance and microstructure properties of a prospective multilayer protective coating on carbon-carbon composite materials are studied. Thermomechanical compatibility of a coating with base material, its thermal stability, thermal shock and cracking resistance are evaluated.

The possibility of evaluating the structural entropy of sheet samples of D16 alloy after aging at 50, 100, 150, and 200°C for 15, 30, 60, 120, and 240 min is considered. A quantitative relationship between the treatment conditions and crystallinity level is established. The effect of the stages of structural changes during aging on the variation of structural entropy is determined.

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

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

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.

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

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

Features of the development of digital twins of thermomechanical steel treatment processes and examples of production tasks solved with their use are considered. The technique of creating digital twins of hot rolling, as well as hot or cold rolling with subsequent heat treatment is described. Adistinctive feature of the digital twin being developed is that in addition to the finite-element model of

Orientation microscopy (EBSD) is used to study structural and textural states through the thickness of pipe steel strips after a controlled thermomechanical treatment. It is shown that texture formation in the form of a selection of components (3 – 7) with a large number of versions of crystallographic orientations, arising with shear phase transformations in accordance with the orientation ratios

The paper discusses combined conditions of saturating martensitic steel with carbon and nitrogen using low-pressure atmospheres. The studied conditions include pre-carburizing, hardening heat treatment, and finishing nitriding, as well as pre-nitriding, subsequent carburizing, and heat treatment. Acomparative analysis of the properties of steels obtained under different combined conditions was performed

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.