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Fang, Jian Hua, Bo Shui Chen, Jiu Wang i Jiang Wu. "Effect of Boron-Nitrogen Containing Modified Soybean Oil Lubricating Additive on Friction and Wear Behavior of Steel-Steel and Steel-Aluminum Alloy Systems". Applied Mechanics and Materials 380-384 (sierpień 2013): 8–11. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.8.
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A type of new environmentally friendly lube additive---boron-nitrogen modified soybean oil was synthesized and characterized by infrared spectrum. Its effect on the friction and wear behavior of steel-steel and steel-aluminum alloy systems were investigated with a four-ball machine and an Optimol SRV friction and wear tester respectively. The morphographies of the worn surfaces were analyzed by means of scanning electron microscopy (SEM).The worn surfaces of the 2024Al alloy block were analyzed by means of X-ray photoelectron spectroscopy (XPS).The results show that the type of modified soybean oil as additives can obviously decrease the wear rate and friction coefficient of steel pair and steel-aluminum frictional pair. Its lubrication mechanism is inferred that a high strength adsorption film and/or tribochemistry reaction film on the worn surface of the Al alloy due the carrier effect of a long chain soybean oil, high reaction activities of nitrogen, electron-deficient of boron and their synergisms.
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Malyshev, Vladimir, Mikhail Gelfgat, Arseniy Scherbakov i Alexey Alkhimenko. "Protection enhancing of threaded connections of light-alloy drill pipes against contact corrosion". E3S Web of Conferences 225 (2021): 03003. http://dx.doi.org/10.1051/e3sconf/202122503003.
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When using light-alloy drill pipes (LAIDP) with steel tool joints, the development of contact corrosion is observed under certain operating conditions. The value of corrosion mainly depends on the difference in electrochemical potential (ECP) of the contacting metals. One of the effective methods for increasing the corrosion resistance of aluminum alloys is the micro-arc oxidation (MAO) method. This is an electrochemical process in combination with micro-arc-discharges phenomena at the anode-electrolyte border, which allows forming ceramic coatings of aluminum oxides on the surface, including its high-toughness and wear-resistant phase - α-Al2O3 (corundum). MAO-technology is a highly efficient and environmentally friendly process. At the forming of such a coating on the threaded part and in the tool joint zone of the pipe, a barrier for contact corrosion between the steel tool joint and the surface of the aluminum pipe is created. In this work, contact corrosion on samples in a pair of 1953T1 aluminum alloy - 40KhN2MA steel in a 5% NaCl solution at 80 °C was investigated. The data obtained showed the effectiveness of using protective MAO-coating to reduce contact corrosion and increase the reliability of the tool joint threaded connection of LAIDP.
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Romero-Arguello, Juan M., Anh-Vu Pham, Christopher S. Gardner i Brad T. Funsten. "Miniature Coil for Wireless Power and Data Transfer through Aluminum". Sensors 21, nr 22 (15.11.2021): 7573. http://dx.doi.org/10.3390/s21227573.
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This paper presents the design and development of miniature coils for wireless power and data transfer through metal. Our coil has a total size of 15 mm × 13 mm × 6 mm. Experimental results demonstrate that we can harvest 440 mW through a 1 mm-thick aluminum plate. Aluminum and stainless-steel barriers of different thicknesses were used to characterize coil performance. Using a pair of the designed coils, we have developed a through-metal communication system to successfully transfer data through a 1 mm-thick aluminum plate. A maximum data rate of 100 bps was achieved using only harvested power. To the best of our knowledge, this is the first report that demonstrates power and data transfer through aluminum using miniature coils.
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Pichugin, D. V. "Influence of lubricant viscosity on wear rate of aluminum alloy/steel friction pair". Chemistry and Technology of Fuels and Oils 21, nr 8 (sierpień 1985): 408–10. http://dx.doi.org/10.1007/bf01110587.
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Subbotin, Oleksandr, Valery Bilozerov, Oleg Volkov, Valeria Subbotinа i Vadym Shevtsov. "FRICTION PROPERTIES OF MАO COATINGS ON ALUMINUM ALLOYS". Bulletin of the National Technical University «KhPI» Series: Engineering and CAD, nr 2 (28.12.2022): 59–63. http://dx.doi.org/10.20998/2079-0775.2022.2.07.
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Aluminum alloys are widely used in mechanical engineering due to their physical and mechanical properties. However, their low wear resistance and burr resistance limit their use in friction nodes. In this regard, parts made of aluminum alloys operating under conditions of sliding friction require surface strengthening, which determines the friction wear parameters. Research works in this direction allow increasing the reliability and service life of friction nodes. Ensuring the compatibility of friction pairs allows reducing the coefficient of friction and, as a result, to increase wear resistance. One of the effective methods of forming wear-resistant coatings on aluminum alloys is the method of micro-arc oxidation (MAO). The use of micro-arc discharges as highly concentrated energy sources to create conditions for high-temperature electrotechnical processes and phase transformations in the surface layer makes it possible to form structures based on high-temperature oxides on the surface of metals, which provides qualitatively new surface properties: high hardness, wear resistance, corrosion resistance in various environments. However, the use of oxide coatings in bearings is mainly due to their high wear resistance and corrosion resistance. Information on the antifriction properties of aluminum oxide-based coatings is limited. The purpose of this work is to determine the coefficient of friction of MAO-coatings on D16 aluminum alloy in a pair with cast iron, steel and MAO-coating under conditions of oil and water lubrication, and to find out the feasibility of using MAO technology to create sliding bearings. The formation of MAO coatings was carried out in an alkaline-silicate electrolyte in the cathodic-anodic mode. The structure and morphology of the working layer of the MAO-coating surface, which works in friction pairs with cast iron, steel and MAO-coating under conditions of oil and water lubrication, was investigated. The benefit of the available porosity of the working layer of the MAO coating, which is 5-10% and contributes to the retention of lubricant in the friction zone, is shown. The phase composition, hardness of the coatings were studied and the coefficient of sliding friction was determined on the SMC-2 friction machine according to the "disk-pad" scheme when using water and oil as lubricants; the load varied from 0.2 to 2 kN, the nominal pressure from 1 to 11 MPa. It was established that the MAO coating has a crystalline structure, the phase composition is high-temperature modifications of aluminum oxide (α-Al2O3 and γ- Al2O3), and the hardness is 18000-20000 MPa. It was established that the coefficient of sliding friction of gray cast iron - MAO-coating, steel - MAO-coating and MAO on MAO decreases to the value of 0.01 - 0.013 under lubrication conditions. It was found that in a pair of MAO-coating - MAO-coating, anti-friction properties are manifested both under conditions of lubrication with oil and water. The low coefficient of friction for the coating-coating pair in the case of water lubrication is explained by the high hydrophilic properties of the oxide contacting surfaces, which makes it possible to recommend them for use in sliding bearings (liners) of hydroturbines. A conclusion was drawn regarding the reasons for the low coefficient of friction of the studied samples. Keywords: D16 aluminum alloy, cast iron, steel, micro-arc treatment, coating, phase composition, crystal structure, aluminum oxides, coating thickness, coating hardness, friction coefficient, antifriction properties
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Faes, Javier, Rubén González, Antolin Hernández Battez, David Blanco, Alfonso Fernández-González i José Luis Viesca. "Friction, Wear and Corrosion Behavior of Environmentally-Friendly Fatty Acid Ionic Liquids". Coatings 11, nr 1 (27.12.2020): 21. http://dx.doi.org/10.3390/coatings11010021.
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This research deals with the tribological behavior and corrosion performance of three novel fatty acid anion-based ionic liquids (FAILs): methyltrioctylammonium hexanoate ([N8,8,8,1][C6:0]), methyltrioctylammonium octadecanoate ([N8,8,8,1][C18:0]) and methyltrioctylammonium octadec-9-enoate ([N8,8,8,1][C18:1]), employed for the first time as neat lubricant with five different material pairs: steel–steel, steel–aluminum alloy, steel–bronze, steel–cast iron and steel–tungsten carbide. These novel substances were previously obtained from fatty acids via metathesis reactions, identified structurally via NMR (nuclear magnetic resonance) and FTIR (Fourier-transform infrared spectroscopy) techniques, and then characterized from a physicochemical (density, water solubility, viscosity, viscosity index and refractive index) and environmental (bacterial toxicity and biodegradability) points of view. The corrosion behavior of the three FAILs was studied by exposure at room temperature, while friction and wear tests were performed with a reciprocating ball-on-disc configuration. The main results and conclusions obtained were: (1) Corrosion in the presence of the three FAILs is observed only on the bronze surface; (2) All FAILs presented similar tribological behavior as lubricants for each tested material pair; (3) XPS (X-ray photoelectron spectroscopy) analysis indicated that the surface behavior of the three FAILs in each material pair was similar, with low chemical interaction with the surfaces.
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Biryukov, Vladimir, i Anton Princ. "DEFINITION OF TRIBOLOGICAL CHARACTERISTICS OF THE ALUMINUM AND SILICON ALLOY DEPENDING ON THE COMPOSITION OF ADDITIVES FOR DIESEL LOCOMOTIVE PISTON". Transport engineering 2022, nr 7 (5.07.2022): 34–42. http://dx.doi.org/10.30987/2782-5957-2022-7-34-42.
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The study objective is to define the influence of various modifiers on the tribotechnical properties of an aluminum and silicon alloy. Determination of the most optimal additives in alloys that would reduce the friction factor and increase the unit load at which friction pairs set in comparison with the starting material, as well as determination of their wear resistance.
Research methods are tests conducted for friction and wear of samples based on aluminum and silicon according to the following: plane (test sample) – the sleeve end (steel 40X), as well as conducting tests with the supply of free abrasive into the friction zone according to the following: flat sample - forming surface of a rubber disc.
Research results and novelty: the influence of modifiers in the aluminum and silicon alloy composition on wear resistance and friction ratio at different loads and sliding speeds in a friction pair with steel are established.
Conclusions: the regularities of changes in the friction ratio from pressure and speed, the load of seizure from the sliding speed are obtained. The wear resistance of samples with various inclusions is higher compared to the base material.
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Rusyn, Iryna, i Vasyl Dyachok. "Wetland meadows of carex acutiformis as a source of bioelectricity of agglomeration atmospheric air pollution and environmental safety of the practices". Environmental Problems 6, nr 3 (2021): 125–29. http://dx.doi.org/10.23939/ep2021.03.125.
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The article presents the assessment of bioelectroproductivity of wetland sedge ecosystems of Carex acutiformis in situ. It was found that it is possible to obtain a bioelectric potential at the level of 864.2-1114.8 mV, depending on external conditions using a pair of electrodes graphite/zinc-galvanized steel and graphite/aluminum. The increase in soil moisture had a positive effect on bioelectric potential parameters. Widespread in Polissya biotopes of sedge have prospects as sources of green plant-microbial energy.
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Napadłek, Wojciech, Adam Woźniak i Agnieszka Laber. "The Use of Laser Texturing the Surface Layer to Modify the Friction Pair Pin-Bushing". Solid State Phenomena 220-221 (styczeń 2015): 708–13. http://dx.doi.org/10.4028/www.scientific.net/ssp.220-221.708.
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This paper presents the methodology and results of laser texturing of the surface layer steel 41Cr4, applied to the manufacture of crankshafts and selected aluminum alloy used for the production of slide bearings (bearings) for internal combustion engines. Laser treatment of the surface layer of this material was carried out using Nd: YAG laser with a wavelength of pulsed laser radiation λ-1064 nm. Application of laser ablation micromachining in sensitive zones of the crankshaft and slide bearing, mainly the surface layer of the friction pair, was aimed to formation of a suitable surface texture containing oil microchannels. Applying different parameters ablative laser micromachining (power density, repetition rate, number of pulses in the same area, the overlap area microchannels), a very interesting stereometry of the surface layer steel 41Cr4 and bearing alloy was obtained. The lubricant had characteristic microchannels, very important in the tribological process of the friction pair crankshaft – slide bearing. Laboratory metallographic tests showed the high dispersion microstructure of martensitic steel 41Cr4 in the superficial zone, melted and hardened. The transition zone was found to be of martensitic-bainitic microstructure and bainite. The microstructures are formed by ultrafast phase transformations over time crystallization of alloy Fe-Cr-C from the liquid phase (microhardness in the range of 550-680 HV0.05). The microstructures appear in the adjacent area to the lubricant microchannels produced during laser texturing. The studies of laser texturing the sliding layer of slide bearing made of aluminum alloy, destined to cooperate with tribological function pin engine crankshaft are preliminary results. The positive results: high repeatability of the process texturing regular geometric shape microchannels and ease process control. In the best version, technological preliminary tests showed the following oil microchannels dimensions: depth of about 3.2 microns, width 47 microns; it is a promising result.
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Kreivaitis, Raimondas, Milda Gumbytė i Jolanta Treinytė. "Investigation of tribological properties of environmentally friendly ionic liquids as a potential lubricity improving additives for water-based lubricants". Industrial Lubrication and Tribology 74, nr 3 (21.01.2022): 294–301. http://dx.doi.org/10.1108/ilt-06-2021-0213.
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Purpose This paper aims to investigate the tribological properties of two protic ionic liquids used as lubricity-improving additives in the water. Their concentration was optimized for different metal friction pairs including bearing steel, stainless steel and aluminum alloy. Design/methodology/approach In this study tribological properties were investigated by using a ball-on-plate reciprocating tribometer. Three different friction pairs were selected: bearing steel-bearing steel; bearing steel-stainless steel; bearing steel-aluminum alloy. To optimize the concentration of investigated protic ionic liquids four concentrations were selected. Wettability was investigated using the droplet method. The corrosiveness of additive-loaded water was investigated using the iron chip method. Findings The results show that by using protic ionic liquids the lubricity of water could be greatly improved. However, the friction pair material and additive concentration play a significant role. The positive tribological effect was attributed to the polarity of the additive molecule which tends to form an adsorption layer. The polarity of molecules also leads to better surface wettability. It was also found that both investigated protic ionic liquids can improve the anticorrosion properties of water. Originality/value To the best of the authors’ knowledge, this is the first study to present a complex investigation of tribological properties of two protic ionic liquids as additives in the water. In this case, three different metal friction pairs and four additive concentrations were investigated. The results could be interesting to those who are working in the field of water-based lubricants and luck for multipurpose lubricity-improving additives.
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Hao, Yishu, i Yajun Shi. "Contact stress analysis for a pair of aluminum matrix composite helical gear and steel worm". Journal of Reinforced Plastics and Composites 34, nr 3 (30.12.2014): 213–21. http://dx.doi.org/10.1177/0731684414566632.
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Barry, G. W., i J. S. Goodling. "A Stefan Problem With Contact Resistance". Journal of Heat Transfer 109, nr 4 (1.11.1987): 820–25. http://dx.doi.org/10.1115/1.3248187.
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A Stefan problem in which a semi-infinite molten material at the fusion temperature solidifies as a result of imperfect thermal contact with a cooler semi-infinite solid is considered. The contact resistance, due to surface roughness, is modeled by a convective boundary condition. Biot’s variational principle is used to reduce the coupled partial differential equations to a pair of coupled ordinary differential equations that are solved numerically. The position of the moving boundary as a function of time is given for both bismuth and aluminum solidifying on stainless steel.
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Осадчук, С. О., Л. І. Ниркова i О. І. Букет. "Вплив числа електродних пар на похибку електрохімічного давача поляризаційного опору для вимірювання шидкості атмосферної корозії". Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 140, nr 6 (13.02.2020): 112–24. http://dx.doi.org/10.30857/1813-6796.2019.6.11.
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Investigate the influence of the number of electrode pairs of multi-electrode co-surface electrochemical polarization resistance sensors on the error of measurement of polarization resistance, and, accordingly, on the corrosion rate under atmospheric conditions. Method of polarization resistance. Determination of the contact area of electrodes with the aluminum substrate by the method of obtaining a print on a flat surface. Graphical modeling of the contact surface of the sensing element from the steel electrodes to the anodized aluminum substrate. Investigation results of the influence of the electrode pairs number of multielectrode cosurface electrochemical polarization resistance sensor, sensing element of which is steel-made and is located on the thermoconductive anodized aluminum substrate, on the measurement error of corrosion rate in atmospheric conditions are presented. It was shown that in determining of the corrosion rate by polarization resistance method the increasing of the electrode pairs number of sensor from one to four increases the reproducibility of measurement results and their convergence with the gravimetric data. Taking into account the form of prints of four-pair sensitive element, the area of surface contact of sensitive element of eight-pair sensor with aluminum substrate was graphically simulated. It was taken into account during modeling, that the design feature of the sensor is a possibility of full contact of one pair of the electrodes with the substrate, which explains the reason of measurement error increasing with increasing the number of electrodes’ pairs. Increasing the pairs number from one to four and then to eight decreases the part of surface of sufficiently tight contact of sensitive element with aluminum substrate from 100% to 50% and further up to 30 %. The extreme dependence of the measurement error on the number of electrodes pairs due to the increasing area of the working surface of the electrodes and reducing the area of tight contact with the aluminum heat-conducting base was revealed. It was found that four electrodes pairs for the presented sensor design is optimal. It was established that the reason of increasing of the error of polarization resistance measurement under atmospheric conditions and, accordingly, the corrosion rate, by using the electrochemical multi-electrode co-surface sensors of polarization resistance under increasing the electrode pairs number (from one to eight) is the decreasing in the surface part of a sufficiently dense contact of the sensitive element (about two or three times). Another tendency that leads to decreasing in error is decreasing in the error of setting the corresponding polarization while increasing the total area of the electrodes. The extreme dependence of this error on the number of electrode pairs with a minimum for a four-pair sensor is shown. The problem of uncontrolled variation of the measurement error by using the polarization resistance sensor of the considered construction was solved and the optimal number of electrode pairs (four) was determined. Using such of a sensor will allow to evaluate the corrosivity of the atmospheric air environment with respect to the responsible metal structures and their corrosion state in local corrosion-dangerous places with stable and minimal error.
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Constantin, V., L. Scheed i J. Masounave. "Sliding Wear of Aluminum-Silicon Carbide Metal Matrix Composites". Journal of Tribology 121, nr 4 (1.10.1999): 787–94. http://dx.doi.org/10.1115/1.2834136.
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The sliding wear of an aluminum matrix composite, reinforced with different volume fraction of particles, against a stainless-steel slider has been studied. In dry conditions, i.e., unlubricated tests, the pairs (slider and specimen), wear. When rubbing against an aluminum alloy (unreinforced), the slider does not wear but the aluminum alloy wears quickly by adhesion. In dry conditions, both slider and composite wear, but there is a minimum wear rate for this pair at a critical volume fraction of reinforcing particles. Under lubricated conditions, the situation changes dramatically. The composite no longer wears, but the slider wears very quickly. Under water, results are a compromise between the two previous situations, dry and lubricated. These results are explained by a simple, descriptive mechanism, which takes in account both the effect of the shear rate, due to the sliding action in the composite, and the abrasive effect of the particles. A general relationship, which describes the effect of the applied pressure and volume fraction of particles in the composite, is proposed.
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Zhang, Xiuli, Zhongwei Yin, Qin Dong i Jun Cao. "Experimental comparison of the seizure loads of gray iron journal bearing and aluminum alloy journal bearing under aligned and misaligned conditions". Mechanics & Industry 21, nr 4 (2020): 408. http://dx.doi.org/10.1051/meca/2020038.
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Materials, surface roughness of bearing and shaft, and journal misalignment affect the seizure load of journal bearing. To improve the load carrying capacity of bearing and obtain better friction pair, this paper studies experimentally the seizure loads of a gray iron journal bearing and two kinds of aluminum alloy journal bearings under both aligned and misaligned conditions. Three shafts are used to study the effects of journal surface roughness and DLC coating. The journal center locus is recorded. Results show that the combination of DLC coating and the aluminum alloy with lower hardness has the largest seizure load and inclined angle, followed by the combinations of DLC coating and gray iron, and 40Cr steel and gray iron. The surface roughness values of bearing and shaft have a considerable negative effect on seizure load, especially for aligned condition.
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Yoshida, Yoshinori, i Takafumi Noritake. "Influence of Layer Number on Mechanical Property of Steel Hollow Sphere Sheet Sandwich Construction". Key Engineering Materials 651-653 (lipiec 2015): 1608–13. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.1608.
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Two sheets of steel hollow sphere sheet (TEC SHEET) are laminated and its mechanical property is investigated by means of stab proof test. The construction is sandwiched by a pair of pure aluminum plates with two kinds of bonding methods. Three point bending test and compression test are conducted for the construction. As the results, stab proof strength is advanced more than that of a single layer sheet. In the bending test, bending load increases with increase of the layer in the sandwich construction. Bending mechanism is investigated and the influence of bonding method on breakage condition of the sandwiches. Compression test for the sandwich construction and foam metal filling construction is conducted and the difference of the energy consumption behavior is investigated.
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Rusin, Nikolay, Alexander Skorentsev i Maksim Krinitcyn. "Features of the Formation of Surface Structures under Dry Friction of Al-30Sn Composite against Steel". Coatings 12, nr 9 (7.09.2022): 1309. http://dx.doi.org/10.3390/coatings12091309.
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Features of the frictional interaction of a sintered Al-30Sn composite, which is used as a coating of bearing inserts, with steel counterbody in the absence of liquid lubricant were studied. The tribological tests were carried out according to the pin-on-disk scheme at room temperature. The friction coefficient μ of the friction pair is increased up to approximately 0.6 during the running-in process. Its growth stops when the stage of steady state friction begins, and then μ fluctuates around some relatively high and constant value. The study of the friction surfaces of the friction pair showed that the aforementioned increase in μ is due to the formation of a discrete transferred layer on the friction track surface and strain hardening of the subsurface layer of the Al-30Sn sample under the action of hard particles of the transferred layer. It was established that tin is transferred on the friction track surface mainly in a composition of wear particles, despite the high content of the solid lubricant in the investigated samples. The wear intensity of the samples subjected to processing by equal channel angular pressing with route A is much lower than that of the sintered (unprocessed) ones. The main wear mechanism of Al-30Sn composites under dry friction against steel is a delamination of the highly deformed subsurface aluminum grains along their interphase boundaries.
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Muravyeva, T. I., I. V. Shkalei, O. O. Shcherbakova i D. L. Zagorskiy. "Study of the Formation of Films of Secondary Structures Upon Sliding of the “Aluminum Alloy–Steel” Friction Pair". Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques 15, nr 6 (listopad 2021): 1326–31. http://dx.doi.org/10.1134/s1027451021060367.
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DASDEMIR, AHMET. "Dynamic response of a pre-stressed bi-layered plate-strip subjected to an arbitrary inclined time-harmonic force". Creative Mathematics and Informatics 26, nr 3 (2017): 255–62. http://dx.doi.org/10.37193/cmi.2017.03.02.
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Within the scope of the piecewise homogeneous body model with utilizing of the three dimensional linearized theory of elastic waves in initially stressed bodies the dynamical stress field problem in a bi-layered plate-strip with initial stress under the action of an arbitrary inclined timeharmonic force resting on a rigid foundation is investigated. The concrete materials such as a pair of Aluminum and Steel are selected. It is assumed that there exists a complete contact interaction between the layers. The mathematical modeling of the problem under consideration is carved out, and the governing system of the partial differential equations of motion is approximately solved by employing Finite Element Method. The numerical results related to the influence of certain parameters on the dynamic response of the plate-strip are presented.
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Chumaevskii, Andrey, Denis Gurianov, Anastasiya Gusarova, Anna Zykova, Aleksandr Panfilov, Evgeny Knyazhev, Vladimir Beloborodov i Leonid Zhukov. "Process Relationship in High-Stress Friction Coupled with Complex Shaped Counterbody and Friction Stir Welding Al-Mg-Sc-Zr Alloy". Materials Science Forum 1049 (11.01.2022): 39–44. http://dx.doi.org/10.4028/www.scientific.net/msf.1049.39.
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Model research tests of plastic deformation, fragmentation and flow of aluminum alloy material of Al-Mg-Sc-Zr system under high loaded friction in pair with a steel counterbody of a complex shape and comparison of the obtained result with the structure formed by friction stir welding have been carried out. The conducted studies show that the structure formed by extrusion of the material from the friction zone and its compaction in the channel of the counterbody is, in general, close in structure to the structure formed by friction stir welding of similar material. The distinguishing features of the structure formed in the model experiments on friction include the introduction into the stirring zone of material with deformed large-crystal structure, increased grain size of the stirring zone, the presence of defects and differences in the geometry of the stirring zone.
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Lee, S. L., i C. R. Ou. "Gap Formation and Interfacial Heat Transfer Between Thermoelastic Bodies in Imperfect Contact". Journal of Heat Transfer 123, nr 2 (12.07.2000): 205–12. http://dx.doi.org/10.1115/1.1338133.
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In this paper, the integration scheme is employed to solve a coupling problem of transient heat conduction and displacement due to thermal deformation. Based on the resulting displacement, gap or contact pressure on the interface of two thermoelastic bodies in imperfect contact is estimated. Such information is then used to determine the interfacial heat transfer between the two thermoelastic bodies. This again affects the temperature distribution and thus the thermal deformation. In the course of heat transfer and thermal deformation, effect of thermal rectification also is taken into account. Numerical solutions of transient and steady-state quantities including gap formation, normal stress, and temperature are demonstrated for a pair of stainless steel and aluminum with conforming shapes. Such an analysis of conduction-deformation interaction based on a finite-difference-like scheme has not been studied in the past.
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Logachev, Konstantin M. "Upgrading a CVD unit for chrome carbide deposition on the inner surfaces of the fuel injector nozzle body of a diesel engine". Agricultural Engineering, nr 3 (2023): 84–90. http://dx.doi.org/10.26897/2687-1149-2023-3-84-90.
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Fuel injector nozzle parts tend to wear out due to abrasive particles of quartz and aluminum oxide penetrating into the fuel. The hardness of quartz abrasive particles exceeds the hardness of work surfaces in 1.4 times, and that of aluminum oxide – in 2.7 times. Strengthening one part of the fuel injector nozzle does not increase the service life sufficiently, so it is necessary to harden both parts of the precision pair. The CVD method is the most promising technology of wear-resistant coating deposition on steel machine parts. It produces carbide-chrome coating with microhardness up to 19 GPa (in vacuum conditions of 100 to 0.001 Pa) at temperatures above 200°C. The analysis of available devices and the review of patents of known solutions on the coating deposition from a steam phase have shown the impossibility of using these devices for restoration of the nozzle body. In this respect, the author developed a new reactor design and a scheme of the CVD unit for the coating deposition on the inner hard-to-reach surfaces of the nozzle body. The developed CVD unit takes into account the factors affecting chromium carbide deposition: thermodynamic conditions, reagent feed, deposition duration, unit parameters, adhesion and coating properties. The CVD unit upgrade results in making chromium carbide coating on the inner surfaces of the nozzle sprayer body, achieving thermodynamic equilibrium of chemical reaction of chromium hexacarbonyl decomposition at temperatures below 200°C (below the low tempering level of 18Х2Н4ВА, 12Х2Н4А and 40ХН2МА steel), and ensuring a controlled supply of a reaction medium to hard-to-reach areas, where refractory metal coatings are formed.
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Kroll-Rabotin, Jean-Sébastien, Matthieu Gisselbrecht, Manoj Joishi i Jean-Pierre Bellot. "Local behavior of inclusions in reactors metallurgical: Aggregation and deposition on the walls". MATEC Web of Conferences 379 (2023): 02003. http://dx.doi.org/10.1051/matecconf/202337902003.
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Populations of inclusions conditioned very early in the alloy production process metals, during the refining and liquid metal treatment stages, are likely to drastically impact mechanical performance, especially fatigue resistance. Control performance of these materials therefore requires control of the inclusion populations, requiring in particular a very good knowledge of the mechanisms which govern their evolution in number and size in refining reactors. Inclusive behaviors in supply chains steel and aluminum have already been the subject of numerical studies at the process scale (Bellot et al., 2014 ; Waz et al., 2016) in which the transport and agglomeration of inclusions are modelled. In order to improve the modelling of key phenomena such as the aggregation and capture of wall inclusions, local simulations, at the scale of an inclusion pair and a layer limit to the wall of a reactor, are carried out here using a lattice Boltzmann method (Sungkorn and Derksen, 2012).
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Chu, Ngoc-Hung, Van-Du Nguyen i The-Vinh Do. "Ultrasonic-Assisted Cutting: A Beneficial Application for Temperature, Torque Reduction, and Cutting Ability Improvement in Deep Drilling of Al-6061". Applied Sciences 8, nr 10 (20.09.2018): 1708. http://dx.doi.org/10.3390/app8101708.
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This paper presents an experimental study of the positive effects of vibration-assisted deep drilling of aluminum alloy Al-6061. The four most important evaluation criteria in drilling—machinability, workpiece temperature, torque, and material removal rate—were chosen to be investigated. Holes with a depth-to-diameter ratio of 13 were drilled by high speed steel (HSS) twist drill bits of 3 mm diameter, using both methods of conventional drilling (CD) and ultrasonic-assisted drilling (UAD). Three levels of axial force of 6 kgf, 9 kgf, and 12 kgf were kept constant for each pair of comparison experiments. It was found that workpiece temperature and torque not only changed from one drill to the other, but were also dependent on the hole depth being drilled. Comparisons were made in-pair between CD and UAD under the same axial force and at the same order of hole numbers. The result shows that the material removal rate with UAD was up to 3.5 times higher than that with CD and the average workpiece temperature and torque in UAD were reduced by 3.5 and 6 times, respectively. Moreover, tool life in UAD was observed to increase from 2.5 to 5 times, in terms of number of holes drilled, compared to that in CD.
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Härtwig, Fabian, Lars Lorenz, Stefan Makowski, Matthias Krause, Carsten Habenicht i Andrés Fabián Lasagni. "Low-Friction of ta-C Coatings Paired with Brass and Other Materials under Vacuum and Atmospheric Conditions". Materials 15, nr 7 (30.03.2022): 2534. http://dx.doi.org/10.3390/ma15072534.
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Vacuum environments provide challenging conditions for tribological systems. MoS2 is one of the materials commonly known to provide low friction for both ambient and vacuum conditions. However, it also exhibits poor wear resistance and low ability to withstand higher contact pressures. In search of wear-resistant alternatives, superhard hydrogen-free tetrahedral amorphous carbon coatings (ta-C) are explored in this study. Although known to have excellent friction and wear properties in ambient atmospheres, their vacuum performance is limited when self-paired and with steel. In this study, the influence of the paired material on the friction behavior of ta-C is studied using counterbodies made from brass, bronze, copper, silicon carbide, and aluminum oxide, as well as from steel and ta-C coatings as reference materials. Brass was found to be the most promising counterbody material and was further tested in direct comparison to steel, as well as in long-term performance experiments. It was shown that the brass/ta-C friction pair exhibits low friction (µ < 0.1) and high wear in the short term, irrespective of ambient pressure, whereas in the long term, the friction coefficient increases due to a change in the wear mechanism. Al2O3 was identified as another promising sliding partner against ta-C, with a higher friction coefficient than that of brass (µ = 0.3), but considerably lower wear. All other pairings exhibited high friction, high wear, or both.
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Wang, Guang-hong, Sheng-guan Qu, Zhi-hua Xiong, Fu-qiang Lai, Xiao-qiang Li i Mao-sheng Yang. "Wear behavior and mechanism of a sliding pair of 0. 1C-3Cr-2W-V nitrided steel rubbing against an aluminum bronze alloy". Journal of Iron and Steel Research International 23, nr 3 (marzec 2016): 281–88. http://dx.doi.org/10.1016/s1006-706x(16)30046-2.
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Hua, Xijun, Xuan Xie, Bifeng Yin, Peiyun Zhang, Jinghu Ji, Hao Wang i Yonghong Fu. "Tribological performance and self-lubricating mechanism of the laser-textured surface filled with solid lubricant in rolling friction pair". Industrial Lubrication and Tribology 70, nr 2 (12.03.2018): 371–84. http://dx.doi.org/10.1108/ilt-07-2017-0210.
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Purpose This paper aims to find out the tribological performance and self-lubricating mechanism of the laser-textured surface filled with solid lubricant in rolling friction pair. Design/methodology/approach The textures on the surfaces of GCr15 bearing steel were produced by acousto-optic Q diode-pumped yttrium aluminum garnet laser with the technology of “single pulse one time, repeating at intervals” and filled with composite solid lubricant. The tribology tests were conducted on the MMW-1A universal friction and wear testing machine. Findings It was found that the solid-lubricated micro-textured surface can reduce the friction coefficient effectively. The MoS2/PI composite solid lubricant works better than the single MoS2 solid lubricant, and the ratio of PI/MoS2 + PI at 20 per cent is the best recipe. The friction coefficient of the sample surfaces decreases first and then increases with the increase in texture densities, and a texture density of 19.6 per cent has the best effect on friction reduction. The friction coefficient of the textured surfaces gradually decreases with the increase in both rational speed and load. For the same texture density, the friction coefficient of textured surfaces decreases slightly with the increase in diameter. Furthermore, the mechanism of “rolling-extrusion-accumulation” occurred on the textured surface can collect the solid lubricant, thereby, improve the effect of lubricating and anti-friction. Originality/value The results of the experimental studies demonstrated the application prospect of laser surfaces texturing combined with solid lubricant in rolling friction pair.
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Lysykh, Stepan, Vasily Kornopoltsev, Undrakh Mishigdorzhiyn, Yuri Kharaev i Zhongliang Xie. "Evaluation of Wear Resistance of AISI L6 and 5140 Steels after Surface Hardening with Boron and Copper". Lubricants 11, nr 2 (29.01.2023): 48. http://dx.doi.org/10.3390/lubricants11020048.
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(1) Background: Boriding is one of the most common methods of thermal-chemical treatment due to its excellent hardness and wear resistance of the produced diffusion layers. However, it has limited application compared to carburizing and nitriding because of fragility and chipping. Introducing another alloying element into the boron media helps avoid those drawbacks and improve other surface properties of the layer. The purpose of this work is to improve the surface mechanical properties of L6 and 5140 low alloy steels by two-component surface hardening with boron and copper. (2) Methods: The treatment was performed by means of a powder-pack method using boron, copper, and aluminum powders in the following proportions: 60% B4C + 20% Al2O3 + 16% CuO + 4% NaF. The time–temperature parameters of the treatment were four hours exposure at 950 °C. Microstructure, elemental, and phase composition were investigated as well as microhardness and wear resistance of the obtained layers. (3) Results: Layers of up to 180–200 μm thick are formed on both steels as a result of treatment. Needle-like structures similar to pure boriding was obtained. The maximum microhardness was 2000 HV on L6 steel and 1800 HV on 5140 steel. These values correspond to iron borides and were confirmed by XRD analysis revealing FeB, Fe2B, and Cr5B3. The wear resistance of both steels was about ten times higher after the treatment compared to non-treated samples. (4) Conclusions: Surface hardening with boron and copper significantly improves the mechanical properties of both alloy steels. The results obtained are beneficial for different tribo-pair systems or three-body wear with abrasion and minimum impact loads.
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Chavdarov, Anatoliy V., i Aleksey A. Tolkachev. "Restoration of internal surfaces of cylindrical parts of small diameters by cold gas dynamic spraying". Tekhnicheskiy servis mashin, nr 3 (20.08.2020): 128–36. http://dx.doi.org/10.22314/2618-8287-2020-58-3-128-136.
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Wear of internal surfaces of cylindrical parts of small diameters is a common defect of equipment used in the agro-industrial complex. There are problems with low powder utilization and lack of a design solution for coating the inner surfaces of cylindrical parts with small diameters. (Research purpose) The research purpose is in evaluating the adhesive and cohesive strength and developing a technology for restoring the internal surfaces of cylindrical parts of small diameters by cold gas-dynamic spraying. (Materials and methods) Authors applied the method of cold gas dynamic spraying. The article presents a device for gas-dynamic coating on the inner surfaces of cylindrical parts and determines the optimal deposition modes for powder consumption and heating temperature. A portable DIMET-403 unit, aluminum oxide powder for surface preparation, a-20-11 aluminum powder, and a steel plate were used for the study. The weight was measured on analytical scales with an accuracy of 0.001 grams. Tests were performed on the adhesive and cohesive strength of the coating on cylindrical samples prepared by mechanical processing, under the most favorable conditions with a duration of deposition equal to 60 seconds. Samples were processed after sputtering on a lathe to obtain a cylindrical belt. (Results and discussion) The values of adhesive and cohesive strength of coatings fit into the range of values suitable for operation, and meet the conditions for obtaining a wear-resistant ceramic coating. The article presents a technology for obtaining a sublayer for the manufacture of ceramic wear-resistant surfaces in a pair of friction piston ring-cylinder. (Conclusions) The developed restoration technology of internal surfaces of cylindrical parts of small diameters by cold gas-dynamic spraying solved the problem of their wear.
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Jamali, A., H. Babaei, N. Nariman-Zadeh, SH Ashraf Talesh i T. Mirzababaie Mostofi. "Multi-objective optimum design of ANFIS for modelling and prediction of deformation of thin plates subjected to hydrodynamic impact loading". Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, nr 3 (22.07.2016): 368–78. http://dx.doi.org/10.1177/1464420716660332.
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Drop hammer impact experiments have been carried out to assess the dynamic plastic response of fully clamped circular and rectangular plates made of aluminum and steel subjected to hydrodynamic impact loading at various energy levels. Also, the effective parameters in forming process are proposed in non-dimensional forms for modeling and prediction of the central deflection of plates using adaptive neuro-fuzzy inference system in conjunction with genetic algorithm and singular value decomposition method. Genetic algorithm is used for optimal scheme of Gaussian membership function’s variables and multi-objective Pareto optimal design of adaptive neuro-fuzzy inference system model. Also, the singular value decomposition method is applied to compute the linear parameters of the adaptive neuro-fuzzy inference system method. The important conflicting objectives of developed adaptive neuro-fuzzy inference system, namely, training error and prediction error, are obtained by dividing date sets into two parts. Hence, various optimal choices of adaptive neuro-fuzzy inference system model are provided which are non-dominated states from each other. Moreover, optimal Pareto front of such model leads to trade-off between the conflicting pair of considered objectives for two series of experiments. The results of this work indicate that multi-objective Pareto optimal design of adaptive neuro-fuzzy inference system predicts central deflection of plates with a good accuracy. In addition, the comparison between the adaptive neuro-fuzzy inference system model and exiting one demonstrates superior performance of the present approach in simulating central deflection of plates.
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Lezhnev, Sergey, Evgeniy Panin i Irina Volokitina. "Research of Combined Process “Rolling-Pressing” Influence on the Microstructure and Mechanical Properties of Aluminium". Advanced Materials Research 814 (wrzesień 2013): 68–75. http://dx.doi.org/10.4028/www.scientific.net/amr.814.68.
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In the development of new technology forming the ultimate goal is increasing of productivity, expansion of range, creating a compact production, capable of rapid reconfiguration for mobile release of the new product. But the main purpose, of course, is improvement the quality of the source material. When used as a raw material of various grades of steel, non-ferrous metals and their alloys, the main aspect of quality improvement is increasing the strength characteristics. Often to increase the strength of deformable metal should be given reduced grain structure, up to subultra and even nano-level. There are several ways to obtain sub-ultra-fine-grain structure of metals and alloys, and one of those ways is a method of severe plastic deformation of the metal, implemented in the whole volume of the deformable metal.On the department "Plastic Metal Working" of Karaganda State Industrial University was previously developed and proposed a new method of combined rolling and pressing in equal-channel step die, which compared to conventional compression in the traditional equal-channel step die ensures the continuity of the process and removes the restrictions on the size of the original pieces. The essence of the method is that workpiece which is pre-heated to a temperature of the beginning of deformation is applied to the forming rolls, which due to contact friction forces captured it in roll gap and pushed through the channels of equal- channel step die. At the exit from the die installed a second pair of rolls, which pulls the workpiece from the die.In the research of the process were made theoretical studies, after which were received the empirical formulas to determine the rolling force in the rolls and pressing force in the matrix. Also were obtained formulas for the kinematic state of the process.Also conducted a simulation of the process in the software package Deform-3D, in which produced the picture of stress - strain state and analyzed the resulting force.In this work, laboratory studies were performed of the combined process. In particular, a laboratory experiment was conducted to implement the combined process of "rolling-compaction", whose main purpose was to research the effect of the scheme on the deformation changes in the microstructure and mechanical properties of the original pieces, made of aluminum alloy AK6.Research of the mechanical properties and microstructure of deformed aluminum billet by this way was found that the implementation of the combined process of "rolling-compression" increases strength properties of aluminum, and reduced plastic properties, and the original grain during deformation is reduced.
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Vaszilcsin, Nicolae, Andrea Kellenberger, Mircea Laurentiu Dan, Delia Andrada Duca i Valentin Laurentiu Ordodi. "Efficiency of Expired Drugs Used as Corrosion Inhibitors: A Review". Materials 16, nr 16 (10.08.2023): 5555. http://dx.doi.org/10.3390/ma16165555.
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Corrosion inhibitors represent one of the most commonly used methods for significantly reducing the corrosion rate of metals and alloys. Adsorption inhibitors have a wide range of applications in cooling water systems, deicing solutions for aircrafts, airports and ways, etching and degreasing solutions, oil pipelines, paints and coatings and metal processing solutions. Adsorption corrosion inhibitors of metals and alloys are generally organic compounds that contain structures with heteroatoms (N, P, S, As, O) in their molecules, having lone pair electrons or π electrons in aromatic rings or multiple bonds. They enable relatively strong interactions between the metal atoms and organic molecules, resulting in a protective layer of organic molecules adsorbed at the metal–corrosive solution interface. Most molecules of active substances from drugs contain similar structures, which is why many drugs have been already tested as corrosion inhibitors. One of the major disadvantages of using drugs for this purpose is their particularly high price. To overcome this impediment, the possibility of using expired drugs as corrosion inhibitors has been investigated since 2009. The present paper is an exhaustive compilation of the scientific published papers devoted to the use of expired drugs as corrosion inhibitors in various aggressive solutions. The inhibitory efficiencies of expired drugs are presented as a function of the studied metal or alloy and the nature of the aggressive solution, as well as the concentration of the inhibitor in such a solution. Research has especially been focused on mild and carbon steel and less on stainless steel, as well as on some metals such as copper, zinc, nickel, tin and aluminum and its alloys. The experimental methods used to assess the inhibitory efficiencies of expired drugs are briefly discussed. Also, the available information on the stability of the active substances in the drugs is presented, although most authors were not concerned with this aspect. Finally, several actions are revealed that must be undertaken by researchers so that the results obtained in the study of the anticorrosive action of expired drugs can be applied at the industrial level and not remain only an academic concern.
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Deng, Yuan Jing, Jun Chao Yu, Kai Quan Xia i Lin Yang. "Corrosion Conditions Analysis of In-Service ACSR Overhead Lines". Applied Mechanics and Materials 446-447 (listopad 2013): 753–58. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.753.
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The corrosion conditions of in-service aluminum conductor steel reinforced (ACSR) overhead lines in typical climate were studied by using macroscopic and microscopic methods. According to its operating environment, the corrosion causes were also analyzed. It is found that the corrosion of the outer aluminum stranded conductors is more serious than other parts. And partial corrosion pits have been found on the outer layers of aluminum stranded conductors. While there is no obvious corrosion appeared on the steel core matrix. Additionally, corrosion products can reduce the corrosion rate of aluminum stranded conductors but accelerate corrosion of the steel core. Through this research, more attention should be paid to monitor the aluminum stranded conductors.
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Ishigaki, T., K. Shibuya, H. Sakaue i S. H. Be. "Sealing technique for aluminum to stainless steel CF flange pairs". Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 12, nr 4 (lipiec 1994): 1705–8. http://dx.doi.org/10.1116/1.579040.
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Леонтьев, Л. Б., А. Л. Леонтьев i К. А. Молоков. "Increasing the durability of precision parts of marine diesel engines by forming composite coatings on the surface of the plunger". MORSKIE INTELLEKTUAL`NYE TEHNOLOGII)</msg>, nr 1(59) (4.03.2023): 73–80. http://dx.doi.org/10.37220/mit.2023.59.1.007.
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Основной причиной отказов плунжерных пар топливных насосов высокого давления (ТНВД) является потеря гидроплотности вследствие увеличения зазора между плунжером и втулкой из-за абразивного изнашивания сопряженных поверхностей трения, а также эрозионного и коррозионного изнашивания. Для восстановления изношенных и повышения долговечности плунжерных пар ТНВД необходимо разработать технологию формирования износостойких покрытий. Наиболее перспективным направлением восстановления и повышения износостойкости является формирование металлокерамических композиционных покрытий на основе гальванического хрома. Основной целью работы является определение оптимальных механических свойств композиционного покрытия на основе гальванического хрома и состава органо-неорганического материала для его модифицирования, обеспечивающих максимальную износостойкость и долговечность прецизионных деталей топливной аппаратуры судовых дизелей. Проведенные исследования позволили установить, что формирование композиционного покрытия на основе гальванического хрома на плунжере позволяет повысить долговечность плунжерной пары по сравнению с хромированным плунжером более чем в три раза при использовании большинства органо-неорганических материалов. Наиболее высокую износостойкость прецизионных деталей и соответственно их долговечность обеспечивает формирование покрытия на основе гальванического хрома с последующим его модифицированием вермикулитом, модифицированным хитозаном. Установлено, что наибольшее влияние на скорости изнашивания покрытия плунжера и стали ХВГ (втулка) оказывает коэффициент трения, меньшее – модуль упругости покрытия. Минимальное влияние оказывает величина упругого восстановления покрытия. Микротвердость покрытия практически не оказывает влияние на скорости изнашивания покрытия плунжера и стали ХВГ в данном диапазоне величин. Модифицирование гальванического хрома органо-неорганическими материалами позволяет существенно уменьшить коэффициент трения в плунжерной паре. Высокое содержание углерода, кремния, алюминия и марганца в поверхностном слое свидетельствует об образовании износостойкого металлокерамического покрытия. The main reason for the failures of plunger pairs of high-pressure fuel pumps (injection pumps) is the loss of hydraulic density due to an increase in the gap between the plunger and the sleeve due to abrasive wear of the mating friction surfaces, as well as erosive and corrosive wear. To restore worn-out and increase the durability of plunger pairs of injection pumps, it is necessary to develop a technology for the formation of wear-resistant coatings. The most promising direction of restoration and improvement of wear resistance is the formation of metal-ceramic composite coatings based on galvanic chromium. The main purpose of the work is to determine the optimal mechanical properties of a composite coating based on galvanic chromium and the composition of organo- inorganic material for its modification, ensuring maximum wear resistance and durability of precision parts of the fuel equipment of marine diesel engines. The conducted studies have allowed us to establish that the formation of a composite coating based on electroplated chromium on the plunger makes it possible to increase the durability of the plunger pair in comparison with the chrome plunger by more than three times when using most organo-inorganic materials. The highest wear resistance of precision parts and, accordingly, their durability is ensured by the formation of a coating based on galvanic chromium, followed by its modification with vermiculite modified with chitosan. It is established that the coefficient of friction has the greatest influence on the wear rate of the coating of the plunger and the steel of the plunger bushing, the modulus of elasticity of the coating has the lesser. The amount of elastic recovery of the coating has a minimal effect. The microhardness of the coating has practically no effect on the wear rate of the coating of the plunger and plunger bushing in this range of values. Modification of electroplated chromium with organo-inorganic materials can significantly reduce the coefficient of friction in the plunger pair. The high content of carbon, silicon, aluminum and manganese in the surface layer indicates the formation of a wear-resistant metal-ceramic coating.
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Watakabe, Takahito, Goroh Itoh i Yuji Hatano. "Visualization of Diffusive Hydrogen". Materials Science Forum 654-656 (czerwiec 2010): 2903–6. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2903.
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In recent years, the use of hydrogen as a clean energy has been paid attention to in terms of the prevention of global warming. Tanks composed solely of steel and cylinders consisting of aluminum liner reinforced with C-FRP in the surrounding are used to store high-pressure hydrogen gas in hydrogen stations and in fuel cell vehicles, respectively. On the other hand, hydrogen embrittlement has been known to occur in some metallic materials under several certain conditions. Also, it has been generally known that the environmental hydrogen that invades the material during services plays major role in hydrogen embrittlement. For this reason, investigations on the behavior of environmental hydrogen in metallic materials are needed. In this study, the behavior of environmental hydrogen in pure aluminum, 6061 aluminum alloy and 7075 aluminum alloy has been investigated by means of tritium autoradiography.
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Voznesensky, N. K., i B. T. Velichkovsky. "Aerosols of low cytotoxic metal oxide condensates as an etiological factor of occupational cardiomyopathy". PULMONOLOGIYA, nr 4 (28.08.2008): 47–51. http://dx.doi.org/10.18093/0869-0189-2008-0-4-47-51.
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Smelters working with aluminum and brass-bronze alloys and electric welders working with carbide and low-alloyed steel develop primary myocardial injury independent on hypertension and coronary atherosclerosis. This injury is characterized by structural disorders such as myocardial concentric and eccentric hypertrophy, concentric remodeling left heart myocardium, non-coronarogenic pain, changes of T-wave in ECG, and cardiac arrhythmias. According to the 10th International classification of diseases, such signs should be considered as cardiomyopathy caused by environmental exposure, namely by fine-particle aerosols of condensates of zinc, aluminum and iron oxides having slow solubility and cytotoxity.
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Korosteleva, Elena, Ivan Nikolaev i Victoria Korzhova. "Features of the structure formation of sintered powder materials using waste metal processing of steel workpieces". Metal Working and Material Science 24, nr 4 (15.12.2022): 192–205. http://dx.doi.org/10.17212/1994-6309-2022-24.4-192-205.
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Introduction. Manufacturing processes, to one degree or another, are associated with the metal waste production in the form of metal chips. The development of technologies for recycling of waste from mechanical facilities is a popular solution both from the resource saving and from an environmental points of view. Among many traditional approaches to the problem of recycling metal chips, the most interesting may be the method of using chips as one of the components in a powder material. The aim of this work is to analyze the possibility of using metalworking wastes from steel 45 (metal chips) in powder compositions based on titanium and aluminum not only as a source of iron, but also as a possible source of Fe2O3 oxide. Attention to the oxide was paid in terms of initiating reduction reactions in the powder mixture based on titanium and aluminum with the formation of the Al2O3 oxide phase to obtain a metal matrix composite. Research methods: steel chips after processing workpieces from steel 45 were additionally oxidized in water and crushed in a vibrating mill to an average particle size of 300 μm for use in powder compositions with titanium and aluminum powders. Grinded and oxidized chips were mixed with titanium and aluminum powders in various proportions in order to study its interaction with these powder components. The obtained mixtures were pressed in the form of cylindrical samples and sintered in a vacuum furnace at a temperature of 1,000 °C. The phase composition and microstructure were studied using an XRD-6000 X-ray diffractometer with CuKα – radiation and an AXIOVERT-200MAT optical microscope. Results and discussions. It is shown that after milling without coolant, steel 45 chips did not accumulate a noticeable amount of iron oxides, which required additional oxidizing procedures. The interaction of grinded oxidized chips with the components of powder mixtures is considered, and its effect on volumetric changes in compacts and structure formation of metal-matrix composites is shown. The results of optical metallography and X-ray diffraction analysis (XRD) of sintered powder compositions using oxidized ground chips of steel 45 made it possible to evaluate the ongoing processes of structure formation depending on the combination of interacting components, its mutual influence, and the prospects for obtaining composites with a dispersed oxide phase.
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Marinzuli, G., L. A. C. De Filippis, R. Surace i A. D. Ludovico. "A Preliminary Study on Adhesion on Steel Cylinder Filled with Aluminum Foam". International Journal of Metals 2013 (23.12.2013): 1–14. http://dx.doi.org/10.1155/2013/878032.
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In the last decades, metallic foams found commercial and industrial interests, thanks to their physical properties combined with good mechanical characteristics. Metal foam structures are very light and they can be used to reduce the weight of machinery without compromising the mechanical behavior. In this work, a study of the direct junction of metal foam with metal massive components was carried out. Aluminium foams were manufactured starting from commercial foamable precursors. First of all, attention was paid to the repeatability of foaming process. Then, a direct connection between the foamed samples and the steel shell elements was pursued. The materials that seemed to facilitate the formation of an intermetallic layer were studied and the geometry of the steel mould and the most useful way to place the precursor in the steel mould and then in the furnace were considered. To evaluate the produced aluminum foam, morphological and mechanical characterizations were done. Results showed that, keeping constant the contour conditions, it was possible to control the process and a first result, in terms of interaction between foam and mould, was obtained using an X210Cr12 steel as mould material. The SEM observation revealed the presence of an intermetallic phase.
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Mironov, A., I. Gershman i P. Podrabinnik. "Influence of secondary structures formation on tribological properties of aluminum alloys- steel friction pairs". Proccedings of International Scientific Conference "BALTTRIB 2019" 1 (2019): 119–25. http://dx.doi.org/10.15544/balttrib.2019.20.
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Becerril Torres, Osvaldo, Gabriela Munguía Vázquez i Justyna Wieloch. "The effects of US import tariffs on steel and aluminum imports from Mexico". JOURNAL OF INTERNATIONAL STUDIES 15, nr 4 (grudzień 2022): 165–79. http://dx.doi.org/10.14254/2071-8330.2022/15-4/10.
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To this end, mathematical and statistical methods are used to model the effect of tariffs, ex-ante and ex-post, after implementing this trade policy, on exports of aluminum and steel from Mexico to the United States, versus US imports of these metals from the ROW. The results show that the protectionist tariff policy had a structural effect on US imports; likewise, the tariff shock implemented by the United States in June 2018 adversely affected its imports of these goods, both in terms of volume and value. This suggests that bilateral trade may be affected, but the effect is differentiated. The United States may be achieving its objective of protecting its domestic industry or it may impact upwards on the domestic prices of these metals, which could influence the prices paid by the final consumer. For Mexico, trade may be diverted or its export capacity reduced, adversely affecting its trade balance of these metals.
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Reimer, Lars, Alexander Kaluza, Felipe Cerdas, Jens Meschke, Thomas Vietor i Christoph Herrmann. "Design of Eco-Efficient Body Parts for Electric Vehicles Considering Life Cycle Environmental Information". Sustainability 12, nr 14 (20.07.2020): 5838. http://dx.doi.org/10.3390/su12145838.
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The reduction of greenhouse gas (GHG) emissions over the entire life cycle of vehicles has become part of the strategic objectives in automotive industry. In this regard, the design of future body parts should be carried out based on information of life cycle GHG emissions. The substitution of steel towards lightweight materials is a major trend, with the industry undergoing a fundamental shift towards the introduction of electric vehicles (EV). The present research aims to support the conceptual design of body parts with a combined perspective on mechanical performance and life cycle GHG emissions. Particular attention is paid to the fact that the GHG impact of EV in the use phase depends on vehicle-specific factors that may not be specified at the conceptual design stage of components, such as the market-specific electricity mix used for vehicle charging. A methodology is proposed that combines a simplified numerical design of concept alternatives and an analytic approach estimating life cycle GHG emissions. It is applied to a case study in body part design based on a set of principal geometries and load cases, a range of materials (aluminum, glass and carbon fiber reinforced plastics (GFRP, CFRP) as substitution to a steel reference) and different use stage scenarios of EV. A new engineering chart was developed, which helps design engineers to compare life cycle GHG emissions of lightweight material concepts to the reference. For body shells, the replacement of the steel reference with aluminum or GFRP shows reduced lifecycle GHG emissions for most use phase scenarios. This holds as well for structural parts being designed on torsional stiffness. For structural parts designed on tension/compression or bending stiffness CFRP designs show lowest lifecycle GHG emissions. In all cases, a high share of renewable electricity mix and a short lifetime pose the steel reference in favor. It is argued that a further elaboration of the approach could substantially increase transparency between design choices and life cycle GHG emissions.
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Apostolova, R. D., i E. M. Shembel. "Corrosion processes in battery systems based on non-aqueous electrolytes (a review)". Voprosy Khimii i Khimicheskoi Tekhnologii, nr 5 (październik 2021): 3–20. http://dx.doi.org/10.32434/0321-4095-2021-138-5-3-20.
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The article presents some new results of the studies of corrosion processes in lithium battery systems with non-aqueous electrolytes. The following processes are considered: electrochemical corrosion of positive and negative electrodes, corrosion of structural materials, and electrochemical and chemical decomposition of non-aqueous electrolytes, which occurs simultaneously with the main electrochemical process. The main attention is paid to the role of corrosion processes on current collectors of current sources. Corrosion processes on aluminum current collector and stainless steel current collector for positive electrodes of lithium batteries are particularly considered. An important role of corrosion in the degradation of the lithium battery is emphasized. Case studies on corrosion in positive electrodes and lithium electrode are mentioned. Considerable attention is paid to the contact corrosion in aircraft, with an emphasis on the need for further studies of this process. The proposed corrosion mechanisms are considered.
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Mouralova, Katerina, Radim Zahradnicek, Libor Benes, Tomas Prokes, Radim Hrdy i Jiri Fries. "Study of Micro Structural Material Changes after WEDM Based on TEM Lamella Analysis". Metals 10, nr 7 (14.07.2020): 949. http://dx.doi.org/10.3390/met10070949.
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Wire electrical discharge machining is an unconventional machining technology that is crucial in many industries. The surface quality of the machined parts is carefully monitored, but the condition of the subsurface layer also plays a crucial role, especially in case of defects occurrence such as cracks or burnt cavities. The subsurface layer of individual materials is affected differently due to wire electrical discharge machining. For this reason, this study was carried out focusing on a detailed analysis of transmission electron microscope (TEM) lamella made of Ti-6Al-4V titanium alloy, AlZn6Mg2Cu aluminum alloy, pure molybdenum, Creusabro 4800 steel, and Hardox 400 steel. The attention was first of all paid to the concentration and distribution of individual elements in the recast layer and also in the base material, which was often affected by wire electrical discharge machining. Further, a diffraction analysis was performed for each TEM lamella in the adhesive area and in the base material area. In order to assess the macro-effects on the machined material, the topography analysis of the machined surfaces and the morphology analysis were performed using electron microscopy.
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Marinis, Thomas, i Berj Nercessian. "Hermetic Sealing of Stainless Steel Packages by Seam Seal Welding". International Symposium on Microelectronics 2010, nr 1 (1.01.2010): 000720–30. http://dx.doi.org/10.4071/isom-2010-wp5-paper6.
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Welded stainless steel packages offer a number of advantages relative to those fabricated from kovar or aluminum metals and braze sealed. They are highly resistant to corrosion, especially in aqueous or elevated temperature environments, are mechanically stronger, dramatically so at temperatures above 100°C, exhibit lower outgassing rates, and have better vibration characteristics. Since welded stainless steel packages do not require over plating to facilitate braze sealing, combined material and fabrication costs are lower than kovar or aluminum packages. Also, unlike kovar, stainless steel is nonmagnetic, which is advantageous in many electronic applications. For sealing stainless steel packages, we elected to use seam sealing rather than laser welding for two reasons. Seam sealing subjects the package contents to lower thermal excursions than laser welding because less material is melted to achieve a weld in seam sealing. Second, seam sealing confines the molten material between the cover and package, where as laser welding produces a surface filet. Consequently, there is more opportunity for molten metal to splatter or react with the atmosphere in laser welding than in seam sealing. We successfully developed a process to weld a 2 millimeter thick cover onto a box with dimensions of 75 mm long by 50 mm wide by 15 mm deep using a seam sealer. The box walls were 1 mm thick and were penetrated by a dozen glass insulated feedthrus on one side. Both cover and box were fabricated from 316L stainless steel. A combination of analytical and finite element modeling were used in conjunction with a designed experiment to optimize the process variables of roller angle, speed and pressure, weld current, pulse shape, duration and spacing, number of weld passes, and sealing atmosphere. Weld quality and seal integrity were evaluated by leak testing before and after environmental stressing, mechanical testing and metallographic cross sectioning. The effects of component dimensions and tolerances on seal integrity were also investigated. Particular attention was paid to cover flatness, flange thickness, and tightness of fit between the cover and box. The process development was concluded by conducting a qualification experiment that used the optimized process parameters with controlled variation about their nominal values. A 100% yield of sealed boxes was obtained. These test articles were then subjected to various environmental screening tests, which were all passed with no failures.
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Pados, Gábor, Alexandra Kemény, Benedek Szovák, Dóra Károly i Imre Norbert Orbulov. "Fabrication of In-situ Syntactic Aluminium Foam-Filled Steel Tubes". Acta Materialia Transylvanica 6, nr 1 (2023): 38–41. http://dx.doi.org/10.33924/amt-2023-01-07.
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In all areas of industry, when choosing a material, compromises must be made since there is no material with all the properties that are preferential for any use. In the automotive sector, lighter and less dense materials can provide a considerable advantage, for example, lower fuel consumption due to weight reduction. Specialists dealing with materials science within metal foams have been trying to exploit the low density, high specific strength and high energy absorption capacity of metal foams in as many ways as possible for a long time. This research describes the one-step production method of syntactic metal foams with an aluminum matrix infiltrated into a thin-walled steel tube, intended to create functional structures with a strong adhesive bond and metal foam filling in a feasible way.
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Alisin, V. V., B. V. Pokid’ko, M. N. Roshchin, T. V. Silova i G. A. Simakova. "Studying colloidal greases with hard nanoparticles of aluminum silicates used to reduce wear of steel friction pairs". Journal of Friction and Wear 34, nr 6 (listopad 2013): 460–65. http://dx.doi.org/10.3103/s1068366613060020.
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Iseki, H., R. Sowerby, D. Bhattacharyya i P. Gatt. "A Theoretical and Experimental Study of a Curved Strip Compressed by a Flat Plate". Journal of Applied Mechanics 56, nr 1 (1.03.1989): 96–104. http://dx.doi.org/10.1115/1.3176072.
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The quasi-static loading of a curved strip compressed by a flat, rigid plate is considered, with particular reference to large deformations and the ensuing buckling behavior. Experiments were performed on curved strips of constant width but of different thickness. The strips were initially deformed to a fixed radius of curvature and stress relieved before pinning the ends. The span was held constant at about 305 mm. The deformation characteristics have been analyzed using an incremental finite element technique. Particular attention has been paid to modeling the situation when a node contacts the plate and the condition for separation of the strip from the plate. The predicted loads and deformation modes agreed well with experimental results from tests on steel and aluminum specimens. The experimental and theoretical procedures are pertinent to the study of dent resistance of sheet metal stampings, particularly automotive panels.
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Schmid, Philipp, i Mathias Liewald. "Experimental Determination of Heat Transfer Coefficients for Forming of Stainless Steel Sheets Considering Process Conditions and Deep-Drawing Film". Key Engineering Materials 554-557 (czerwiec 2013): 1501–8. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.1501.
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Heat transfer coefficients are playing an important role in forming of metastable stainless steel sheets. Metastable austenitic stainless steels are highly influenced by heating of forming tools due to generation of latent heat during forming process. Strain-induced martensite formation and hence the TRIP-effect is directly coupled with the temperature development within forming tools as well as the temperature induced by heat controlled tools. Measurements of heat development in serial deep drawing processes are showing the need for an accurate determination of heat transfer coefficients considering actual process conditions. Heat transfer coefficients were determined with a simple and easy applicable measurement device for tool materials AMPCO 25 and cold work tool steel EN 1.2379 in combination with aluminum, austenitic EN 1.4301 and ferritic EN 1.4016 stainless steel grades. Special attention was paid to production-related individual influences such as surface conditions, lubrication and deep drawing film. Experiments were accomplished between 1-15 N/mm² showing high influence of intermediate media on heat transfer between forming tool and part and serve as boundary conditions for fully thermo-mechanical coupled forming simulations. A strong influence of deep drawing film, lubrication and surface pressure on heat exchange could be determined and this basic knowledge is seen as mandatory for dimensioning of heat controlled metal forming tools. Finally the experimental determined results are discussed and compared to common heat transfer models and similar experiments from literature.
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Xingrun, Chen, Qian Zhangxin i Pan Jixiang. "Characteristics and formation mechanism of MgO-enriched inclusions in 2507 super duplex stainless steel during LF refinement". Metallurgical Research & Technology 119, nr 5 (2022): 516. http://dx.doi.org/10.1051/metal/2022075.
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Herein, we present the formation mechanism and characteristics of MgO-enriched inclusions in 2507 super duplex stainless steel (SDSS) during the ladle furnace (LF) refining process using a combination of thermodynamic calculations and experimental approach. The compositional analysis reveals that two types of inclusions exist in 2507 SDSS after aluminum (Al) de-oxidation during LF refining process, i.e., CaO-SiO2-Al2O3-MgO and Al2O3-MgO inclusions. Furthermore, the inclusions are transformed into CaO-(SiO2)-Al2O3-MgO inclusions after calcium (Ca) treatment. In addition, the presence of [Mg] lowers the CaO and Al2O3 content of CaO-(SiO2)-Al2O3-MgO, forming MgO-enriched multi-component inclusions. Thermodynamic analysis confirms that the reaction of [Mg] with CaO and Al2O3 can occur in the temperature range of 1500 to 1600 °C during the LF refining process, however, the reaction between [Mg] and SiO2 is thermodynamically not feasible. Overall, the current study demonstrates that more attention should be paid to the MgO-enrichment of inclusions during LF refinement of SSDS.