ISSN (print): 0036-0295, ISSN (online): 1555-6255 Editor-in-Chief: Konstantin V. Grigorovich Publisher: Pleiades Publishing Indexed in: RUS White List (level 3), Scopus, Web of Science (ESCI)
Analysis of the Structure of the Adsorbed Polymer Layers on the Surfaces of Metal Oxide Microparticles Using Digital Image Processing
The shapes and the sizes of metal oxide particles in polymer-stabilized disperse systems subjected to mechanical activation are considered. The digital processing of images of metal oxide particles is used to determine the parameters of the particles and the adsorbed polymer layers and to find the density change dynamics in an adsorbed layer.
Phase States of Carbon, Oxygen, Sulfur, Phosphorus, Silicon, and Lead Impurities. Thermodynamics of Formation and Kinetics of Removal of the Impurities in a Cast ZhS36-VI Nickel Superalloy
The results of thermodynamic analysis of the phase compositions of carbides, oxides, sulfides, phosphides, and silicides are presented. Their amounts in a ZhS36-VI alloy at various contents of impurities in an initial charge in various melting periods are indicated. The thermodynamics of binding such impurities as carbon, oxygen, sulfur, phosphorus, and silicon with refining additives into solid compounds before their removal from a melt is considered. The kinetics of carbon and lead removal during high-temperature refining is calculated.
Determination and Comparison of the Microhardness of Hardening Coatings
An indentation technique for measuring and comparing the microhardness of hardening coatings, which takes into account the scale factor, is proposed and explained. This technique is experimentally shown to be more valid in terms of estimation and comparison of the microhardness of thin hardening coatings.
Application of DAFS for the Estimation of the Elemental Composition of Tool Nanostructures
DAFS, which can be used to solve the problems of tool nanostructures, is considered. It requires special-purpose equipment and can be used individually or in combination with other methods. Examples of studying the anomalous diffraction structure of some nanomaterials are studied.
Contamination of a Recirculated Powder Material during Selective Laser Synthesis
The contamination of the recirculated powder, namely, the material retained after the selective laser sintering of VZh159 and EP648 alloys, is studied as a function of the geometry of a part. The contamination of the recirculated powder is shown to depend mainly on the complex geometry of the part with a long perimeter of its contours and supporting elements rather than on the area of the section to be sintered. The main source of the contamination of the recirculated powder is represented by ejected particles, i.e., secondary granules, which form during a local microexplosion in the focal laser spot on a powder layer. The laws of ejection formation during synthesis are determined as functions of the type of part element to be synthesized.
Development of a Technique to Simulate the Injection Molding of Metallic-Powder-Filled Polymers
Apart from subtractive machining technologies, additive and net-shape replication technologies are being developed and hybrid technologies appear. In particular, PIM (MIM, CIM) technologies, which belong to both powder metallurgy and casting, have been formed. As in other hi-tech production processes, the mathematical simulation of injection molding process is widely used in PIM technology to produce high-quality products, to estimate design and technical solutions, and to avoid the expensive trial-and-error method.
Structure and Tribological Properties of the Wear-Resistant Coatings Deposited Using Flux-Cored Wires Modified by Tantalum and Tungsten
Test flux-cored wires for arc spraying technology are developed. Tantalum and tungsten powders are selected as modifying additives. A PGSR-4 (Ni–Cr–B–Si) commercial powder is the basis of the powder material. The structure of the modified coatings is studied by metallographic analysis. Wear tests of the modified coatings are performed by slipping friction. The friction coefficients and the roughness characteristics are measured.
Deformation Characteristics of the Aerobraking Shell Material
The deformation characteristics of silica fabric with a thermal barrier coating, which is used for the production of the ballute-type aerobrake of a descent module, are estimated. A rubberized fabric strip is subjected to uniaxial tensile tests to failure. Various finite-element simulation approaches to the deformation of the fabric are considered.
Algorithm for the Optimization of the Technological Conditions of Forming Epoxy-Matrix-Based Composites
A technique is developed to optimize the curing conditions when temperature is increased to a given value. The influence of the heating kinetics is studied, and an optimization algorithm is developed using the criteria of the minimum time consumption at the stages before and after gel formation in a binder. The process time is simulated with the Femap software package with allowance for the thermophysical properties of the binder in the liquid and gel states. The simulation results obtained for various heating kinetics are presented. In the optimization regime, the heating rate is found to be 5 K/min before and after the gel formation point.
Technologies of Production of Layered Composites
Two technologies of single-part production of layered composites are considered, the main technological operations are normalized, and the properties of the prepared materials are considered. A nonwoven material with a honeycomb structure is used as one of the components of the layered composite material. The properties of the nonwoven material, foam plastic, honeycomb fillers, and spheroplastics are compared. The total time of impregnation of a layered composite material is theoretically and experimentally studied.
Technological Heredity during the Production and Operation of Structural Materials
The influence of technological heredity factors on the quality indices of parts and products made of polymer composite materials is considered. A technique is developed to take into account the technological heredity factors using the theory of catastrophes. To formalize the technological heredity factors, we propose to use logical functions to form models to predict the change in the quality of a structural material during the entire life cycle of a product. The proposed models can be used to estimate the fracture kinetics for many materials qualitatively.
Climatic Workability of the Polymer Composite Materials Used for Repairing Machines
The properties of the polymer composite materials produced at negative temperatures are studied. The workability indices during repair with polymer materials at negative temperatures are considered. A qualitative criterion, namely, an integral coefficient, which takes into account the errors in each technological operation, is proposed to estimate the workability.
Analysis of the Prospects of Ultrajet Diagnostics for Estimating the Wear Resistance of Bimetallic Tool
Ultrajet diagnostics is used to analyze bimetallic knives for rotary crushers, and a polymer powder is introduced in a jet to imitate the operating conditions of the equipment. The correlation between the cavern depth formed during ultrajet action on a knife and the geometric parameters of the wear of its cutting edge is shown to be high.
Formation of Nickel–Phosphorus Coatings Applied on the Components Manufactured from Nonferrous Metals and Alloys
Some theoretical concepts about the internal stresses in an elastic coating and ways for relaxing of them are reported. These concepts are used in predicting the physicomechanical properties of nickel–phosphorus coatings. The role of surface curvature of a coated component and the layer thickness and the effect of heat treatment on the internal stresses after nickel-plating are considered. Moreover, the effect of heat treatment on the adhesive strength of coating, its wear-resistance, hardness, and fatigue strength is studied.
Consumable Tool for Coating Deposition by Joint Deformation of the Base and Tool Materials
A coating made of an Al–5Mg aluminum alloy is deposited onto a substrate of the same alloy due to the joint deformation of the base and tool materials via friction. A mathematical simulation is used to choose the geometry of the tool that ensures its operability and stability during coating deposition. One-layer and multilayer coatings and butt joints of 2-mm-thick sheets are formed. The joints have a fine-grained structure with the grain size that is smaller than the grain size in the substrate by a factor of 5–10. The microhardness distribution across the deposited layers is nonuniform: the hardness increases from the substrate to the upper layer.
Mechanical Characteristics of Steels with a Gas-Phase Nickel Coating
A promising method of corrosion protection of steel parts in chemical engineering is a gas-phase coating, which has a high density and chemical stability to the influence of fluorine and good adhesion to substrate over entire coating area even for parts of complex shapes. The characteristics of the static and fatigue fracture of BSt.3sp, 40, and E10 steels are considered after coating with gas-phase nickel of different thicknesses (5, 10, 20, 50, and 100 μm) at various substrate temperatures (130, 160, 180, and 200°C). The gas-phase nickel coating 30 μm thick of steel parts can be considered useful due to its high chemical stability and the simplicity of the technological process in spite of some decrease in the mechanical characteristics.
Elemental Composition and Microhardness of the Coatings Prepared on Faced Aluminum Alloys by Plasma Electrolytic Oxidation in a Silicate–Alkaline Electrolyte
Owing to their high microhardness, corrosion resistance, and heat resistance, the oxide ceramic coatings formed by plasma electrolytic oxidation (PEO) find ever-growing usage for various purposes in many industries and, in particular, for maintenance. One of the methods widely used for the maintenance of aluminum alloys products is argon-arc facing. As the materials for facing, alloys of various grades, such as AK9M2, AK5, and AMr6, are used. The electrolytes widely used for PEO are aqueous silicate–alkaline electrolytes, in particular, KOH—Na2SiO3. To find a correlation between the chemical composition of an oxidized faced aluminum alloy and the microhardness of coatings formed on the alloy, X-ray spectrometry analysis is performed. The performed analysis and the determined distribution of chemical elements across the coating thickness allow us to estimate the mechanism of plasma electrolytic oxidation and the correlation between the electrolyte composition, the chemical composition of faced aluminum alloy, and the element composition of the hardened layer.
Structure of the Modified Layer Prepared by Nitriding of Carbon Steel with a Zinc-Filled Coating
The nitriding of a grade 45 carbon steel with a zinc-filled coating (ZFC), which was preliminary formed by cold galvanizing, is considered. The microstructure and the chemical and phase compositions of the modified layer are studied experimentally. It is found that the nitriding leads to the formation of a transition zone in the steel substrate, which is located under ZFC and results from the diffusion of zinc and nitrogen in iron.
Technological Methods for Increasing the Life of Machine Components
A combined technology is developed to increase the service life of machine components. It combines the advantages of “cold” gas-dynamic (supersonic) spraying and plasma electrolytic oxidation and can be used to deposit high-quality coatings onto tractor parts. The interaction of particles with a surface during gasdynamic spraying is theoretically estimated, and rational spraying conditions are chosen. The service properties of the deposited coatings are experimentally studied.
Life Cycle of Products Made of Polymer Composite Materials
The life cycles of products made of metal and polymer composite materials are considered, and their common and distinctive features are determined. Using the mirror of a space antenna (made of carbon-filled plastic) as an example, we analyze the influence of auxiliary materials on the quality indices. A technique is developed to determine the influence of auxiliary materials on the phase composition (polymer matrix content is determined by thermogravimetry). A structure for forming carbon-filled plastic products using vacuum infusion and a system for the implementation of competitive design-technological solutions are presented for the manufacture of carbon-filled plastic products.
Selective Laser Melting of Corrosion-Resistant Steel
The structure formation in corrosion-resistant steel during laser melting is studied. The results of investigation of the morphology and the granulometric and chemical compositions of a CL20ES steel powder, which was prepared by melt dispersion with a high-pressure inert gas, are reported. It is shown that samples characterized by the highest density and microhardness are prepared using a converging laser beam.
Mass Transfer of a Nanocrystalline 5BDSR Alloy during Low-Voltage Electrospark Treatment
A mathematical dependence is obtained to calculate the electrode material mass transferred from an anode to a cathode during low-voltage electrospark treatment. The mass transfer of a nanocrystalline 5BDSR alloy is experimentally studied. The difference between the calculated and experimental data is at most 10%.
Increasing the Service Life of Farming Machines by Surface–Energy Modification of Tribounit Surfaces by Fluocarbon Surfactants
The methods of decreasing the surface wear in tribounits and increasing the service life of agricultural machines by modifying tribounits by fluocarbon surfactants are considered, and the technology of application of a protective molecular film, electrolytic fluorination, and copolymerization reaction are discussed.
Microstructure and Mechanical Properties of Light Cellular Constructions Made of a VT6 Alloy by Selective Laser Melting
Functional-gradient materials with a variable density can be manufactured by varying a configuration of the base elements of cellular constructions, which is important when designing medicine implants with improved characteristics. The microstructure of cellular elements fabricated by selective laser melting has been studies, and the mechanical characteristics of samples with cellular elements have been determined.
Action Time and Amplitude–Frequency Characteristics of Gas Pulses during the Treatment of Steel Machine Components by Pulsed Gas Flows
The problems of optimization of the amplitude–frequency characteristics of a gas flow affecting metallic articles and blanks and the gas pulse duration are considered. This optimization ensures the required increase in the mechanical and service properties at the minimum treatment time. The influence of the gas flow velocity on these properties is analyzed.
Designing and Calculation of Extruded Sections of an Inhomogeneous Composition
Extruded sections with various versions of reinforcing elements are considered. In particular, a T‑shaped stringer made of an aluminum alloy and reinforced at its base is studied. A sample is reinforced by a wire placed along the stringer length. Wires made of titanium, nickel, and 30KhGSA steel were used a reinforcing material. Wires of two diameters, namely, 4 and 6 mm, are considered for each material. For each case, we performed numerical and analytical estimations of the temperature stresses in the composite stringer, which are caused by cooling from 500 to 0°C. The numerical calculation is conducted by the finite-element method with the Femap and Nastran software packages. The analytical calculation is executed using Hooke’s law with allowance for temperature terms and the Lamé solution. The stringer–core combination, where the core is inserted in the stringer without interference, is analyzed. Equivalent stress distributions in the stringer and the core are obtained for all versions under study. The strengths of all versions of reinforcing are estimated.
Maximum Feed in Forging in a Radial-Forging Machine with the Jigging Motion of Head Levers
The radial reduction of a billet in a radial-forging machine (RFM) with the jigging motion of levers with heads is considered. The maximum metal feed in forging is determined to effectively choose the machine drive elements. To this end, we derive expressions to describe the motion of working tool during radial forging in RFM and equations for the drive power balance and the nonuniformity of machine running. In addition, the condition for the acceleration of the drive flyweight during the idle time of RFM is determined. Parametric analysis is performed to determine the maximum billet feed into heads for a number of electric engines and various reduced flywheel weights used in RFM with the jigging motion of heads.
Engineering Estimation of the Error of Bending of Angle Blanks in a Tool Die
The challenging problem of ensuring the accuracy of sizes in bending followed by elastic springback of angle parts, which form a wide class of aircraft elements, i.e., stringers, stiffening ribs, and lattice wheel and wing elements, is considered. The purpose of this work is to develop a technique for engineering estimation of the angle error in bending an angle blank in a tool die. The proposed technique reflects the physical features of springback in bending in a tool die, is characterized by simplicity, and provides the accuracy of estimating the angular error that is sufficient for engineering practice. This technique can be used to solve a number of practical problems.
Experimental Estimation of the Technological Indices of the Machining of Metals by Edge Tool at an Ultrahigh Cutting Speed
The wear and the surface quality of various structural materials are studied after machining at ultrahigh cutting speeds. The periodicity of cutting is shown to decrease the wear of tool, to reach the stability of tool that is economically efficient, and to achieve the surface quality that is higher than that after conventional cutting.
Core Structure Formation in the Joints Fabricated by Friction Stir Welding of Metals with Polymorphic Transformations
The microstructures of the weld core, the heat-deformation-affected zone, and the heat-affected zone having formed during the friction stir welding (FSW) of 12Kh18N10T steel and OT4-1 and VT-1 alloys are studied. The weld core of the solid-state FSW welded joints made of the metals and alloys that undergo polymorphic transformations is shown to form under structural superplasticity due to corporative recrystallization processes and phase transformations.
Comparative Estimation of the Qualities of the Titanium Alloy Joints Made by Traditional Argon-Arc Welding and Innovative Arc Welding with Alternate-Pulsed Supply of Different Protective Gases
The welded joints of VT20 and OT4-1 titanium alloys formed by an innovative method (alternate-pulsed supply of argon and helium) are shown to have smaller grains and a wider melting zone in comparison with traditional argon-arc welding due to a more effective mechanical and thermal action of an arc in the weldpool. In addition, the innovative joints have a higher plasticity, a smaller scatter of the hardnesses over the cross section, and a higher welding speed.
Effect of Machining of the Edge of a Blank Made of a Polymer Composite Material on Its Water Resistance
The influence of the method of machining of the edges of carbon-filled plastics on their water absorption is experimentally studied. The water absorption of composite materials is shown to depend on both the method of machining of the edges and the plastic material. The results of structural investigations demonstrate that milling is the most suitable method for machining the edges of the polymer composite material parts produced by vacuum infusion.
State of Stress in Cylindrical Parts during Transverse Straightening
Straightening by transverse bending followed by hardening by surface plastic deformation based on transverse spinning of cylindrical parts by flat plates is suggested to restore the shape of distorted low-rigidity cylindrical parts, such as shafts and axles. The Ansys Workbench software package is used to estimate the state of stress in a cylindrical part during transverse straightening. The distributions of the working and residual stresses over the cross section of a cylinder are obtained as a function of the relative reduction.
Technology of Borating Hardening of the Chaff-Cutter Drum Knives in a Grain Harvester Combine
The methods of hardening of the chaff-cutter drum knives in a grain harvester combine are analyzed. The wear resistances of 65g steel samples hardened by quenching and borating and heating by high-frequency currents are compared. The results of field tests of the hardened knives are presented. These results are used to propose a design for a hardening coating. A two-coil induction heater is suggested for simultaneous heating of both face edges of a knife.
Key Differences between the Technology of Production of GTE Disk Blanks from Nickel Superalloy Granules and the Technology of Isothermal Deformation: A Review
The differences between the chemical compositions, the technologies of melting and remelting, and the heat-treatment conditions of the granulated and deformed nickel superalloys used for the production of GTE disks are considered. The efficiency of using a metal is analyzed for the disk blank fabricated by HIP and is compared with isothermal deformation. The quality control methods applied in the modern Russian practice are compared.
Near-Surface Layer during the Heterogeneous Heterophase Oxidation of Metals and Alloys and the Related Chemical and Technological Aspects
In many cases, when metals and alloys are oxidized under the continuous regeneration of the direct oxidant taken in the amounts comparable with catalytic amounts, the near-surface layer of surface deposits of the products of oxidation of the metal and the reduction of the oxidant of the metal can be considered as a local zone of the macrocyclic stage of regeneration of the oxidant of the metal. The transfer of this stage to the volume phase is admissible and sometimes reasonable if the product of the reduction of the direct oxidant of the metal is soluble in the volume phase to a sufficient extent and the metal oxide is almost insoluble in the volume phase, where the metal exists in a higher oxidation state, or metal peroxide is used as an oxidant. If the indicated solubility of the reduction product of the primary oxidant of the metal is too low or entirely absent, its transfer to the volume phase due to the mechanical failure of the near-surface layer results in progressive self-retardation and also, in many cases, in the nearly entire termination of the oxidation process. The facts of the presence and mechanical failure of the near-surface layer on the metal and alloy favorable from the viewpoint of chemistry and technology are considered.
Low-Temperature Oxidation of Metals and Alloys for Processing Secondary Raw Materials into Chemical Products
The process with two specially selected and synchronously working oxidants, one of which directly oxidizes the metal to form the products of its reduction and another oxidizes this product with the regeneration of the first oxidant consumed in the oxidation of the metal, is shown to be the most appropriate for the processing of metals and alloys. The doses of the used oxidants and the composition of the target product are determined. The processes occurring during the processing are considered.
Quality Management in Manufacturing and Technological Systems
This article discusses the peculiar features of quality management in modern manufacturing and technological systems with consideration for risk-based thinking, in particular, which characterizes quality as a measurable and estimable factor, its indices, existing major categories of quality management, how and when they are applied, as well as their distinctive features.
Improvement of the Processing of Sulfate Lead Raw Materials Containing Noble Metals
The problems of the processing of sulfate lead industrial products containing noble metals, which are related to lead reduction after partial sulfidizing in an alkali melt at ~600°C followed by the extraction of the present noble metals to molten lead, are studied. The process provides deep recovery of lead and extraction of noble metals.
Comparative Analysis of the Mechanical Properties of the Friction Stir Welding Joints of Various Aluminum Alloys
The technological features of friction stir welding of the most widely used aluminum alloys, namely, Al–Si, Al–Mg, and Al–Mg–Mn, are considered and generalized. The structure and the mechanical properties of the welded joints of these alloys are analyzed.