The most commonly quenching process for carburizing gears is the oil-quenching (OQ) and salt-quenching (SQ), and finite analysis and comparison of OQ and SQ on the carburizing gear ring were performed. Wherein, the accurate simulation of gear carburization was obtained by the alloying element coefficient for diffusion coefficient and experiment validation. The heat transfer coefficients measured by the inverse heat transfer method was used to the temperature simulation, and the gear distortion mechanism was analyzed by the simulated results. By the comparison of OQ, SQ had higher cooling capacity in the high temperature region and slow cooling rate in the temperature range where martensite transformation occurs. The martensite transformation was more sufficient, and the compressive stress of the tooth was greater in the SQ. The tooth showed a drum-shaped and slight saddle-shaped distortion in the OQ and SQ, respectively. The simulated distortion results have good consistency with the measured results, and the SQ distortion was more uniform and stable based on the measured results.

This study utilizes Ti-8Nb-4Co alloys added to different proportions of Mo2C powders (1, 3, and 5 mass%) by the vacuum sintering process of powder metallurgy and simultaneously vacuum sinters the alloys at 1240, 1270, 1300, and 1330°C for 1 h, respectively. The experimental results indicate that when 3 mass% Mo2C powders were added to the Ti-8Nb-4Co alloys, the specimens possessed the optimal mechanical properties after sintering at 1300°C for 1 h. The relative density was 98.02%, and the hardness and TRS were enhanced to 69.6 HRA and 1816.7 MPa, respectively. In addition, the microstructure of vacuum sintered Ti-8Nb-4Co-3Mo2C alloys has both α and β-phase structures, as well as TiC precipitates. EBSD results confirm that the Mo ₂C in situ produced TiC during the sintering process and was uniformly dispersed in the grain boundary. Moreover, the reduced molybdenum atom acted as a β-phase stabilizing element and solid-solution in the titanium matrix.

The paper outlines the material and technological aspects of fine (whiteware) ceramics. Particular attention has been paid to the professional nomenclature of fine aluminosilicate ceramics as used in the past and today. Attention was drawn to this mostly overlooked and poorly studied problem. The reason for the durability problems of some semi-vitreous porcelain and faience materials has been explained. The microstructures of porcelain materials – historic as well as contemporary – have been presented in comparative terms, including the technical material, with a distinction and analysis of the basic phases that build up the shard. Generally similar parameters of microstructure and phase composition were found for all tested materials.

The 0.05 mm-thick 304 stainless steel foil was annealed within the temperature range from 950℃-1100℃ for 10 minutes to obtain different microstructures. And micro-deep drawing experiments of stainless steel foils with different tissue structures were conducted to obtain relevant material forming properties influenced by dimensional effects. On this basis, the influence of the microstructure characteristics on the forming performance of 304 stainless steel foil and the quality of the cup formed by using micro-drawing was studied, and its mechanism was discussed. It can be seen from the results that the stainless steel foil annealed at 950℃ exhibits poor forming performance, and the wrinkle phenomenon of the deep-drawn cup is obvious. At the annealing temperature of 1050℃, the quality of the deep drawing cup is significantly improved. When the annealing temperature reaches 1100℃, with the increase of the annealing temperature, the crystal grains size increase sharply, and the coarse-grain effect causes the uneven plastic deformation effect to be obvious. Besides, the drawing quality is obviously deteriorated. The observation of the microstructure of the deep drawing cup shows that the forming effect of the drawing cup is poor due to the rolling defects and the coarse grain effect. The 304 stainless steel drawing cup annealed at 1050℃ enjoys the best forming effect.

The aim of the study was to determine the influence of the amount of a commonly used binder in foundry work, furfuryl resin – on the course of the thermal regeneration of used moulding sand. The thermal regeneration procedure was carried out at a temperature of 525°C, the required temperature determined according to a specific procedure, and a lower and less effective temperature of 400°C. On the basis of the ignition losses, the influence of the regeneration temperature on the effects of the procedures carried out was compared. It was found that 400°C was too low to effectively clean the binder matrix, but that the more resin in the spent sand, the more intense the cleaning effect. When the required regeneration temperature for furfuryl resin of 523°C was used, higher binder degradation kinetics were observed due to the additional energy supplied to the process from the combustion of a large amount of organic material in the moulding sand.

In this investigation, the surface characteristics of Nickel based superalloy Inconel-625 were evaluated by the electrical discharge machining with used cooking oil-based biodiesel as a dielectric. Nickel-based superalloys find wide applicability in numerous industries due to their specific properties. The Cu electrodes of various densities prepared by atomic diffusion additive manufacturing process were used for machining. A comparison of the performance was made based on average surface roughness. The Design-expert software was used for experimental design and parametric analysis. The outcome demonstrated that bio-dielectric fluid produced improved surface characteristics. The surface roughness was observed to reduce. The surface micrograph obtained from scanning electron microscopy also confirms a better surface finish of bio-dielectric fluid over EDM oil. The surface roughness was shown to be most significantly influenced by the discharge current, with the other parameters having little or no effect. The results showed that for bio-dielectric, the lowest Ra was 0.643 µm, and for EDM oil, the highest value of 0.844 µm. The slightest difference in roughness value for two dielectric fluids was 0.013 µm, and the highest difference was 0.115 µm.

Cube Satellites are miniaturized satellites used for space research with a mass of not more than 1.33 kg per unit. They are widely used in space applications because of its low cost of manufacturing and flexibility of applications. Since, they use commercial off-the-shelf components, thermal consideration of internal components of 1-unit cube satellites becomes a necessity. In this paper, transient thermal analysis of a 1-unit cube satellite is conducted to analyze its behavior during the first 29 seconds of orbit insertion from the launch vehicle. Transient thermal analysis yielded a temperature range that exceeded the optimum limit. As a result, to reduce heat dissipation, two main types of thermal management systems for satellites: active control and passive control systems are included. To maintain critical components at their operating temperature, a passive thermal control is implemented. Thermal strap and multi-layer insulation are used to analyze internal components of 1-unit cube satellite. Using graphite fiber thermal strap and aerogel multi-layer insulation for internal components, the 1-unit modular cube satellite is found to be more suitable under low earth orbit conditions.

The application of titanium alloys is limited due to their low surface hardness and wear resistance, especially for parts operating under friction and contact loads. One of the most widely used technologies for the thermochemical treatment of titanium alloys is gas nitriding. A new method in this direction is surface plasma gas nitriding using indirect arc plasmatrons operating in a chamber with a controlled nitrogen atmosphere. In the present work, the changes in the phase transformations, microstructure, and surface hardness of titanium alloy Ti-8Al-1Mo-1V after plasma gas nitriding at the power of 18 kW, and 25 kW for a time between 5 and 30 minutes are studied. The plasma gas nitriding with the indirect plasmatron of the titanium alloy produced continuous surface layers. Analysis of the surface showed the presence of TiN and TiO2. The thickness of the plasma gas nitrided layers ranges between 100 μm and 350 μm, depending on the technological parameters.

Bioactive glass (BG) can be utilized as a replacement and regeneration material for orthopaedic and orthodontic. However, a load-bearing structure requires good mechanical properties to withstand high stress, in addition to good bioactivity properties. In this research, BG and cordierite (BG-cord) composite was fabricated to improve BG’s mechanical properties. The mechanical strength of the BG-cord was investigated. Both BG and cordierite were synthesized separately using the glass melting method. The synthesized BG and cordierite powders were used to fabricate BG-cord using a composition variation from 10 to 50 wt.%. The composite with 30 wt.% cordierite demonstrated the highest diametral tensile strength (DTS), 14.01 MPa.

Aluminium matrix composites offer a combination of properties such as lower weight, higher strength, higher wear resistance and many more. The stir casting process is easy to use, involves low cost and is suitable for mass production compared to other manufacturing processes. An in-depth look at recently manufactured aluminium matrix composites and their impact on particle distribution, porosity, wettability, microstructure and mechanical properties of Al matrix composites have all been studied in relation to stirring parameters. Several significant concerns have been raised about the sample’s poor wettability, porosity and particle distribution. Mechanical, thermal, and tribological properties are frequently studied in conjunction with variations in reinforcement proportion but few studies on the effect of stirrer blade design and parameters such as stirrer shape, dimensions and position have been reported. To study the effect of stirrer blade design on particle distribution, computational fluid dynamics is used by rese­archers. Reported multiphysics models were k-ε model and the k-ω model for simulation. It is necessary to analyse these models to determine which one best solves the real-time problem. Stirrer design selection and analysis of its effect on particle distribution using simulation, while taking underlying physics into account, can be well-thought-out as a future area of research in the widely adopted stir casting field.

The study was intended to determine the effect of the input condition of the 17-4PH steel on the microstructure, mechanical properties and stress state of welded joints. The steel adopted for testing was in the solution condition at 1040°C, the aged condition at 550°C/4h and the overaged condition at 760°C/2 h + 620°C/4 h. Samples of 17-4PH steel, after heat treatment processed with different parameters, were electron beam welded (EBW). The microscopic observation (LM, SEM/EDS) showed that the microstructure of the weld consisted of martensite with a δ-ferrite lattice. In the heat-affected zone (HAZ), transformed martensite was found with evidence of niobium carbides. The results of hardness testing revealed the different nature of the hardness profile with the condition the material before the EB welding process. The hardness profile of the HAZ of the welded samples in the as-solution (ES2) and overaged (ES12) condition was varied (from about 340 HV to 450 HV). However, in the aged condition specimen of 17-4PH steel (ES22) showed a similar hardness level, at around 370 HV. The solution condition (ES2) had the highest strength properties R_m 1180.6 MPa with the lowest elongation A 7.6% of all samples tested. The aged welded specimen (ES22) retained high strength R_m 1103.4 MPa with a better relative elongation A 10.1%, whereas the overaged welded specimen (ES12) saw a reduction of strength R_m 950.4 MPa with an improvement in plastic properties A 18.8%. Obtained results showed a significant effect of the input steel condition on the obtained EB welded joints.

Quaternary ammonium salt (QAS) Hyamine 1622 and benzotriazole (BTAH) were used to form a protective layer on copper surface to resist the corrosion by immersing the copper into the inhibitors-containing solutions. The inhibitor’s anticorrosion properties are studied in neutral 3.5 wt.% NaCl medium by anodic polarization, Tafel polarization, electrochemical impedance spectroscopy (EIS) and OCP exposure. The surface characterization is analyzed by Contact angle(CA) measurement, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy(SEM). The electrochemical tests show that they can act as single inhibitor to form a passive layer to resist Cu corrosion, and the anticorrosion properties of Cu can be improved by using binary Hyamine 1622/BTAH inhibitors. XPS results indicate that both BATH and Hyamine 1622 molecule can be chemisorbed onto the copper surface and make complex films with Cu species. CA measurement revealed the enhancement of hydrophobicity by combining QSA with BTAH. OCP exposure in neutral medium for 72 h evidently reveals that the passive layer formed by binary inhibitors decreases the pit corrosion. Better hydrophobic nature and more compact passive layer give rise to excellent inhibition properties of binary inhibitors.

This study analyses the three-point bending behavior of Nylon 12 (PA12) specimens produced using two additive manufacturing technologies (i.e., fused filament fabrication and selective laser sintering). A Nylon 12 commercially available filament (from Fiberlab S.A.) was selected to employ the fused filament fabrication method (FFF) with a Prusa 3D desktop printer, whereas Nylon 12 sintering powder (from Formlabs Inc.) was chosen for selective laser sintering (SLS) using a benchtop industrial SLS platform, Formlabs Fuse 1, with a powder refresh ratio of 30%. The bending strength and flexural elasticity moduli were determined by following ISO 178:2019 standard specifications to assess the effect of two different technologies on the mechanical behavior of three-point bending specimens produced in three distinct build orientations (i.e., 0°, 45°, and 90°) relative to the printing platform. One-way ANOVA analysis, Tukey’s HSD, and Games-Howell tests are considered to assess the statistical variability of experimental data and compare the mean values of bending strength and flexural moduli. The testing results for the three orientations under question show notable differences and interesting similarities either in terms of strength or elasticity response for a significance p-level of 0.05.

Through the powder metallurgy technique, alloys of the eutectic composition of the Zn-Al system were manufactured (22.3 wt.%Al), reinforced with Ag additions (0.5, 1, 2.5, 5 wt.%), with subsequent annealing heat treatment at three different temperatures; 100, 150 and 200°C for 1 hr. X-ray diffraction, optical microscopy and mechanical tests were performed on the resulting samples. The addition of Ag favors the formation of alpha and beta compounds with Al and Zn respectively, which improves the compressive strength of the alloy. However, with the presence of Ag the hardness is decreased. On the other hand, the application of an annealing heat treatment, shows no significant effect on the evaluated properties of the alloy. The microstructure of the alloys resulted in the presence of very small grains smaller than 1 mm and with rounded morphology.

WC-8Co cemented carbide was prepared by a high-temperature liquid phase sintering in argon at 5-200 Pa. Three microtextured grooves with a spacing of 500, 750, and 1000 μm were prepared on the surface of WC-8Co cemented carbide. TiAlCrSiN multi-element hard coating was deposited on the WC-8Co cemented carbide microtextured surface with multi-arc ion plating technology. The Vickers hardness and fracture toughness of coated and uncoated WC-8Co cemented carbide with or without a microtextured surface were investigated. The effect of different microtextured spacing on the interface bonding strength of the TiAlCrSiN coating was analyzed. The results show that with the reduction of the microtextured spacing, the Vickers hardness of the cemented carbide slightly decreases, and the fracture toughness slightly increases. The microtextured surface can improve the interface bonding strength between the coating and the substrate. The smaller the microtextured spacing, the larger the specific surface area and the higher the surface energy, so the interface bonding strength between the coating and the substrate increases.

Dual-phase steels have received extensive attention in autobody frame manufacturing due to the resulting characteristics of an interesting combination of ductile ferrite and hard martensite. Moreover, the ductile ferrite and hard martensite lead to heterogeneous deformation in the boundary between the two phases. Then, geometrically necessary dislocations (GNDs) are created to accommodate a lattice mismatch due to the deformation incompatibility of the boundary in straining. In this study, a new empirical GND model is developed, in which the GND density is a function of local plastic deformation; the GND density is distributed in the phase boundary in accordance with an “S” model of material plastic strain. The boundary conditions are applied to define the parameters. The proposed model is verified with DP600 steel. The effects of the GNDs and the width between ferrite and martensite on the strain hardening of DP600 steel are evaluated.

The main purpose of the work was to determine the powder influence of the powder preparation on the microstructure and properties of iron-based sinters used as a metallic-diamond matrix. The sinters obtained from a mixture of comercial powders were used for research. A mixture of powders was selected for the tests, in which the mass fractions of individual powders were as follows: 60% Fe, 23.8% Cu, 4.2% Sn and 12% Ni. The powders were pre-mixed in a Turbula mixer and next a part of material was subjected to milling in a ball mill. Sintering was performed using hot-pressing technique in a graphite mould. The investigated properties of the sinters were concerned density, porosity, hardness, oxygen content, static tensile test and analysis of microstructure. Spot chemical analysis revealed the presence of Fe solution, Cu solution and the presence of iron oxides oxides. Nickel atoms were present throughout the sinter volume. The obtained test results showed that the presented sinter has good functional properties (hardness and thermal expansion) and can be used as a diamond-metal composite matrix in diamond tools.The microstructure and mechanical properties of sinters were investigated.

Refractories are the basic material for the construction of the lining of a melting furnace used, among other things, in the foundry industry. The article describes a comparative study of the influence of the type of moulding on the quality of the finished refractory product. A method for making products from refractory materials was proposed and a test methodology was developed. The results, based on a classic study of the quality of these materials, confirm a strong influence on the quality of the materials obtained in terms of reduced porosity and homogeneity of pore size.

AISI 1045 steel has the characteristics of high strain rate, large strain, and sharp rise in temperature during high-speed deformation process, resulting in a concentrated deformation band and fine structure. In this work, the microstructure of submicron-sized grains in AISI 1045 steel material formed under 10 ⁶ s ^–1 during a high speed cutting process was examined. To reveal the dynamic evolution mechanism of the AISI 1045 microstructure, the continuous dynamic recrystallization theory was introduced. The results show a high dislocation density which favor the formation of small angle grain boundaries during the high speed cutting process. Kinetics calculations that use continuous dynamic recrystallization mechanisms prove that the recrystallization size is constant when the strain rate ncreases from 10 ³ s ^–1 to 10 ⁶ s ^–1, and the transition time is reduced from 6×10 ^–5 s to 4×10 ^–8 s. The recrystallization grains were gradually formed during the deformation of the material, not generated after the deformation.

The paper presents the results of the analysis of physical phenomena associated with the degradation processes of the surface layer of polymeric materials. During the interaction disturbance of ultraviolet radiation, atoms are knocked out of the polymer chains, thus breaking the macromolecules, which leads to the disturbance in the structural stability of the materials. The standardised test samples obtained using the injection moulding method were subjected to the degradation process in natural and accelerated conditions in the UV Test device. The degradation process in laboratory conditions was carried out during 750 hours with the use of lamps with a wavelength of 313 nanometers and an irradiation level of 0.76 W/m ², which corresponds to a period of 2 years in natural conditions. Using of thermogravimetric TGA and differential scanning calorimetry DSC analysis, the influence of energy applied from lamps and the energy reaching the earth’s surface on the change of melting enthalpy ∆ H_m, quantitative index of the crystalline phase and the temperature of phase changes were determined.

The aluminum alloy performance gradient plate was prepared by friction stir joining. Analysis results of the macro morphology, microstructure, and hardness of the aluminum alloy performance gradient plate prepared under various parameters show that when the feed speed of the stirring tool is 250 mm/min, the downward pressure of the stirring tool is 6.6 mm, and the rotation speed of the stirring tool changes from 200 rpm to 800 rpm. The macroscopic morphology of the aluminum alloy gradient plates prepared by the method first changed from burr to smooth, and vice versa. There is a different cross-section morphology of the prepared aluminum alloy gradient plates, however, the aluminum alloy plates are stirred and involved with each other, and the grains of the prepared plates are refined. The hardness of the upper and lower surfaces of the aluminum alloy gradient sheet decreases, whereas that of the upper surface of the side increases, and that of the middle and bottom sides also decreases. However, the hardness of the middle side of the sheet prepared with the rotation speed of the stirring tool at 800 rpm increases, but that of the bottom side still decreases. Obtained through analysis that the performance of the aluminum alloy gradient sheet prepared at the stirring tool rotation speed of 500 rpm increases in equal proportion to achieve a good performance gradient change.

This paper conducts low temperature welding tests on Q460GJC thick plate (60 mm), and based on the basic theory of phase transformation structure evolution, a three-dimensional microstructure evolution analysis method for large welded joints is established, and the analysis of the evolution process of multi-layer and multi-pass weld structure under the low temperature environment of thick plates is completed. The comparison and analysis of test and numerical simulation results are in good agreement, which proves that the welding phase transformation model realizes the digitalization of metallurgical phase transformation in steel structure welding, and optimizes welding process parameters. It is of great significance to improve the quality of welding products and lay a foundation for predicting the performance of welded joints from the micro level.

The objective of this paper is to develop a Non Destructive Testing (NDT) method for the detection and classification of defects in composite materials at a micro level and to devise methodologies to analyse the corrosion resistance behavior using Scanned Electron Microscope (SEM) imagery. The defects on the Stainless Steel – Molybdenum (SS-Mo) Nanocomposite coating is estimated from their Scanning Electron Micrographs by using Image Processing algorithms. For this, the SS-Mo Nano Composite coatings are fabricated using a DC magnetron sputtering process using an indigenously prepared sputtering target. Depositions are carried out on Glass substrate for the evaluation of structural, morphological, chemical composition and corrosion resistance of the coatings prepared under different conditions (deposition of SS at 300°C and RT (Room Temperature); deposition of SS + Mo at 300°C and RT). The structural and compositional analysis performed with X-ray Diffraction (XRD) and Energy-Dispersive X-ray spectroscopy (EDX) has confirmed the formation of Stainless Steel Molybdenum Composite, when the deposition is at 300°C. The SS-Mo composite deposited at 300°C is also observed to yield high corrosion resistance of the order 0.058 mm/year. A novel texture – morphology based image feature descriptor has been proposed for corrosion resistance to evaluate the composite material in a Non-destructive manner. The analysis of SEM image of the developed coatings using the proposed feature along with machine learning algorithm reveals the superior property for SS-Mo coatings deposited at 300°C which is also demonstrated by the laboratory experiments.

In this work, a new supplementary formula was introduced to modify the Kerner model. This supplementary formula enable the Kerner model to predict the thermal expansion coefficient of multi-phase reinforced composites by normalization of the thermal expansion coefficient, bulk modulus, and shear modulus of the reinforcements. For comparison, the modified Kerner model as well as modified Schapery, the rule of mixtures, and Turner models were used to predict the thermal expansion coefficient of multi-phase reinforced composites 6092 Aluminum Alloy/silicon carbide/β-eucryptite. The results confirm the robustness of the modified Kerner model for predicting the thermal expansion coefficient of composites with multi-phase near-spherical inclusions. It may provide a fine selection to predict the thermal expansion coefficient of multi-phase reinforced metal matrix composites which cannot predict efficiently before.