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A new multi-layer and multi-material hybrid configuration of weld cladding an annealed EN 8 substrate has been developed and investigated. The AISI 410 martensitic stainless steel is used as the bottom and top clad layers and the AISI 2205 duplex stainless steel is used as the middle weld cladding layer which creates a composite multi-material clad structure with distinct interfacial characteristics. Examination of microstructure unveiled lamellar morphology of the top layer with martensitic-austenitic constituents with maximum hardness, whereas the intermediate layer exhibited ferritic-austenitic morphology with lower hardness. The bottom layer exhibited a tempered martensite structure with a relatively smaller grain size and exhibited intermediate hardness. The bottom-substrate interface displaying the highest interfacial hardness, followed by the middle-bottom interface and the top-middle interface in descending order. Incorporation of AISI 2205 in the intermediate contributed to an increased toughness of 30 MPa√m. During the ball-on-flat sliding wear test, the coefficient of friction displayed an intriguing pattern after a critical load threshold. Higher applied loads led to decreased absorbed energy and a reduction in wear track dimensions. Elevated heat levels promoted tribofilm formation, contributing to lower wear rates, with the optimum condition observed at 7 N, displaying the lowest volumetric loss and wear rate. The primary wear mechanism predominantly involved plastic deformation and plowing, with no apparent indications of brittle fracture. [ABSTRACT FROM AUTHOR]

In this research work, aluminum 6063 alloy foam was synthesized through stir casting using varying amounts of titanium hydride as a foaming agent. A comparative microstructural and wear behavior analysis of stir-cast aluminum 6063 alloy and its foam is presented. The oxide and aluminide phases present as intermetallic compounds in the stir-cast aluminum 6063 alloy foam ensure the stability of the synthesized foam. In order to optimize the effect of wear parameters on the tribological properties of stir-cast aluminum 6063 alloy foam, the L933 orthogonal array (OA) was designed and modeled statistically. The tribological properties of stir-cast aluminum 6063 alloy and its foam were evaluated by pin-on-disc tests. The optimal tribological properties of the synthesized foam are 0.29 coefficient of friction, 8.6 N frictional force, and 0.00025 mm3/N-m specific wear rate. The tribological properties of stir-cast aluminum 6063 alloy foam are superior to those of aluminum 6063 alloy and comparable to other aluminum foams described in the literature. [ABSTRACT FROM AUTHOR]

In this study, the microstructural and mechanical properties of sintered NbCN-Ni cermets with various WC contents were investigated. The density and grain size of the NbCN-Ni cermets increased with an increase in the sintering temperature from 1420 to 1510 °C, whereas after WC addition, the average grain size of NbCN decreased significantly. The added WC was initially dissolved in the binder phase and then dissolved in NbCN crystals and formed a white W-rich (Nb,W)CN shell phase and gray Nb-rich (Nb,W)CN core phase structure for WC contents up to 10 wt%. Meanwhile, the formation of the shell-core structure enabled the morphology of NbCN grains to gradually change from polygonal to spherical, which can be attributed to the high solubility of WC in the Ni binder. The hardness and transverse rupture strength (TRS) of the cermets first increased and then decreased with increasing sintering temperature and WC content. At a WC content of 10 wt% and sintering temperatures of 1480 and 1450 °C, the HV 10 and TRS of the cermets reached maximum values of 1405 kg/mm2 and 1280 MPa, respectively. The friction coefficient of the NbCN-Ni cermets decreased from 0.7 to 0.55–0.6 after WC addition. Hence, the cermets exhibited excellent wear resistance because the introduction of WC decreased their friction coefficient and increased their hardness. [ABSTRACT FROM AUTHOR]

Resin matrix composites are commonly utilized in water-lubricated stern tube bearings for warship propulsion systems. Low-speed and high-load conditions are significant factors influencing the tribological properties of stern tube bearings. The wear characteristics of resin-based laminated composites (RLCs), resin-based winding composites (RWCs), and resin-based homogeneous polymer (RHP) blocks were investigated under simulated environmental conditions using a ring-on-block wear tester. Simulated seawater was prepared by combining sodium chloride with distilled water. The wetting angle, coefficient of friction (COF), and mass loss were measured and compared. Additionally, their surface morphologies were examined. The results indicate a significant increase in the COFs for the three materials with an increased speed or load under dry conditions. The COF of the RLCs is the lowest, indicating that it has superior self-lubricating properties. In wet conditions, the COFs of the three materials decrease with an increasing speed or load, exhibiting a pronounced hydrodynamic effect. The COF and mass loss of RWCs are the highest, while RLCs and RHP exhibit lower COFs and mass loss values. The reticulated texture and flocculent fibers on the surface of RLC enhance the heat diffusion and improve the material wettability and water storage capacity. The surface of RWC is dense, and the friction area under dry conditions is melted and brightened. The surface of RHP is smooth, while the worn material forms an agglomerate and exhibits susceptibility to burning and blackening under dry conditions. The laminated formation method demonstrates superior tribological performance throughout the wear evolution process. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this research process, Al 7178 is considered as base material, boron carbide (B4C), Titanium dioxide and Flyash are utilized as reinforcement elements to improve the wear behavior. The sample of the composite is prepared by Stir casting method. The amount of all reinforcements (3%) is constant. As per the central composite design, wear tests are performed on pin on disc apparatus with alteration of factors level. The chosen factors are load (15 N, 25, 35 N) and sliding speed (3, 6 and 9 m/s) and sliding distance (350, 400, 450 m). The observation experiment results shows that Maximum wear rate is recorded as 0.01582 mm3/Nm for a load of 25 N, slide distance of 400 m and slide speed of 6 m/s. The minimum Wear rate is attained as 0.00748 mm3/Nm at parameters combinations of 35N, 450 m and 9 m/s. Analysis of variance (ANOVA) showed that load, and the interaction between load and sliding distance have the most significant parameters on wear rate trailed by sliding speed. [ABSTRACT FROM AUTHOR]

Titanium (Ti) alloys have been widely used in biomedical applications due to their superior mechanical, physical, and surface properties, while improving their tribological properties is critical to widening their biomedical applications in the current era. The present review examines the recent progress made in enhancing the tribological performance of titanium alloys and titanium matrix composites for biomedical purposes. It specifically focuses on the progress made in biomedical coatings, mechanical surface treatment, and developing titanium matrix composites in terms of their processing, tribological testing conditions, and characterization. Despite thorough investigations, the specific testing procedures for evaluating the friction and wear properties of the alloy and/or biomedical component are still uncertain. The majority of researchers have selected test methods and parameters based on previous studies or their own knowledge, but there is a scarcity of studies that incorporate limb-specific tribological tests that consider the distinct kinematic and biological structure of human limbs. Since advanced microscopy has great potential in this field, a variety of advanced characterization techniques have been used to reveal the relationship between microstructural and tribological properties. Many coating-based strategies have been developed using anodizing, PEO, VD, PVD, nitriding, thermal spray, sol-gel, and laser cladding, however; composition and processing parameters are crucial to improving tribological behaviour. Reinforcing component type, amount, and distribution has dominated Ti matrix composite research. Ti grade 2 and Ti6Al4V alloy has been the most widely used matrix, while various reinforcements, including TiC, Al2O3, TiB, hydroxyapatite, Si3N4, NbC, ZrO2 have been incorporated to enhance tribological performance of Ti matrix. Mechanical surface treatments improve biomedical Ti alloys' tribological performance, which is advantageous due to their ease of application. The implementation of machine learning methods, such as artificial neural networks, regression, and fuzzy logic, is anticipated to make a substantial contribution to the field due to their ability to provide cost-effective and accurate results. The microstructural and surface features of biomedical Ti alloys directly affect their tribological properties, so image processing strategies using deep learning can help researchers optimize these properties for optimal performance. [ABSTRACT FROM AUTHOR]

This study looks at how erosive wear affects hybrid composites made by vacuum infusing glass and basalt fibers into an epoxy matrix. The study uses garnet abrasives and a design experiment method to test how resistant these hybrid composites are to erosion at 30°, 60°, and 90° angles of impact. The analysis included three‐dimensional profilometry and scanning electron microscopy. Results show that glass layers enhance erosion resistance, whereas basalt layers increase wear. Key quantitative findings include erosion rates and mass loss, highlighting impingement angle and erosion time as critical factors. At a 30° angle, basalt exhibited more severe wear (erosion rate: 0.8090 mg/g for 20 s) compared to glass (erosion rate: 0.5683 mg/g). Conversely, at 90°, the erosion rate for basalt decreased to 0.3643 mg/g, indicating a decreased sensitivity to this steeper angle. According to the ANOVA, impingement angle and erosion time account for 30.08% and 50.25% of the erosion rate variance, respectively. These findings advance our understanding of material behavior in hybrid composites and emphasize the strategic selection and layering of materials for enhanced durability. This research contributes to developing more sustainable composites, demonstrating natural fibers' potential to improve mechanical properties and erosion resistance. Highlights: Glass layers enhance durability against erosive forces in hybrid composites.Basalt layers accelerate erosion rates, showing a need for strategic layering.Glass fiber reinforcement significantly improves wear performance.Hybrid constructions with glass a top basalt balance flexibility and durability.Emphasizes eco‐friendly advantages of natural materials in composites. [ABSTRACT FROM AUTHOR]

Herein, the tribological and fracture behavior of multilayer 316L–TiC composites produced by the selective laser melting additive manufacturing process is investigated. The results show a robust interface between the layers and no cracks are detected even after a flexural strain of 0.4. The hardness of the composite layers with 5 and 10 wt% TiC increases by 75.5 and 104.8% compared to the hardness of the pure 316L stainless steel layer. Transverse rupture strength measurements show that a layer of pure 316L significantly improves the rupture strength of the multilayer samples. Wear test results show that the inclusion of TiC particles increases wear resistance, with the composite layer containing 10 wt% TiC demonstrating the highest wear resistance. [ABSTRACT FROM AUTHOR]

Recognizing the lightweight nature and superior tribological properties of Al-based metal matrix composites, this study introduces a novel analytical model based on polynomial approximations, offering new insights into the mechanisms of dry friction in AlSi10Mg-SiC composite materials. Key findings highlight a significant reduction in the coefficient of friction (COF) and oscillation amplitudes in SiC-reinforced composites, indicating superior tribological performance compared to their unreinforced counterparts. This behavior is attributed to the effective distribution of SiC particles within the aluminum matrix, which mitigates the stick–slip motion commonly observed under dry sliding conditions. Importantly, the model using polynomial approximations is noted for its simplicity and ease of implementation in practice. The study's conclusions not only underscore the benefits of SiC reinforcement in enhancing wear resistance but also contribute to the broader field of materials science by providing a robust framework for the predictive modeling of COF in various composite systems. [ABSTRACT FROM AUTHOR]

ZG25MnCrNiMo steel samples were prepared by squeeze casting under pressure ranging from 0 to 150 MPa. The effects of pressure on the microstructure, low-temperature toughness, hardness, and impact wear performance of the prepared steels were experimentally investigated. The experimental results indicated that the samples fabricated under pressure exhibited finer grains and a significant ferrite content compared to those produced without pressure. Furthermore, the secondary dendrite arm spacing of the sample produced at 150 MPa decreased by 45.3%, and the ferrite content increased by 39.1% in comparison to the unpressurized sample. The low-temperature impact toughness of the steel at −40 °C initially increased and then decreased as the pressure varied from 0 MPa to 150 MPa. And the toughness achieved an optimal value at a pressure of 30 MPa, which was 65.4% greater than that of gravity casting (0 MPa), while the hardness decreased by only 6.17%. With a further increase in pressure, the impact work decreased linearly while the hardness increased slightly. Impact fracture analysis revealed that the fracture of the steel produced without pressure exhibited a quasi-cleavage morphology. The samples prepared by squeeze casting under 30 MPa still exhibited a large number of fine dimples even at −40 °C, indicative of ductile fracture. In addition, the impact wear performance of the steels displayed a trend of initially decreasing and subsequently increasing across the pressure range of 0–150 MPa. The wear resistance of samples prepared without pressure and at 30 MPa was superior to that at 60 MPa, and the wear resistance deteriorated when the pressure increased to 60 MPa, after which it exhibited an upward trend as the pressure continued to rise. The wear mechanisms of the samples predominantly consisted of impact wear, adhesive wear, and minimal abrasive wear, along with notable occurrences of plastic removal, furrows, and spalling. [ABSTRACT FROM AUTHOR]

In the present study, the densification behavior, microstructural evolution, mechanical properties, and friction behavior of a TiB2/Al8SiCu composite and Al8SiCu alloy manufactured by laser powder-bed fusion (PBF-LB) were systematically investigated. The results confirm that the addition of in situ TiB2 particles into Al8SiCu alloys reduce the volumetric energy density required for a high-density TiB2/Al8SiCu composite. The TiB2 particles promoted a transformation of columnar to equiaxed crystals and the formation of high-angle grain boundaries. The grains on the vertical direction of the PBF-LBed TiB2/Al8SiCu composite were much finer than those of the PBF-LBed Al8SiCu alloy. The addition of TiB2 promoted the grain refinement of the Al8SiCu alloy, of which the average grain size decreased from 15.31 μm to 7.34 μm. The yield strength (YS), ultimate tensile strength (UTS), and elongation (El) of the PBF-LBed Al8SiCu alloy were 296 ± 6 MPa, 517 ± 6 MPa, and 11.7 ± 1.0%, respectively. The PBF-LBed TiB2/Al8SiCu composite achieved a balance between strength and ductility with a yield strength of 328 ± 8 MPa, an ultimate tensile strength of 541 ± 3 MPa, and an elongation of 9.1 ± 0.7%. The increase in strength mainly resulted from grain boundary strengthening, dislocation strengthening, load-bearing strengthening, solid-solution strengthening, and Orowan strengthening, of which the dislocation strengthening and Orowan strengthening were critical. The enhanced hardness associated with the grain refinement and the formation of the in situ TiB2 particles also led to an enhanced tribological performance, of which reductions in the average friction coefficient from 0.655 to 0.580 and wear rate from 1.76 × 10−3 mm3/Nm to 1.38 × 10−3 mm3/Nm were found. [ABSTRACT FROM AUTHOR]

The Ti-6Al-4 V alloy emphasizes its suitability for application in the chemical, aerospace, and automotive industries due to its exceptional mechanical, physical, and chemical qualities. However, the poor tribological properties of these alloys make them unsuitable for interacting environments where wear and friction are encountered. Consequently, this study was conducted to evaluate the impact of thermal treatment settings to tailor the mechanical and tribological properties of Ti-6Al-4 V alloys using duplex heat treatment. The Ti-6Al-4 V alloy was heat treated for 10 to 30 min at a solution temperature of 850 to 913 °C, followed by 60 to 120 min of ageing at a temperature of 450 to 550 °C. The impacts of heat treatment parameters on modifications in microstructure and mechanical characteristics like hardness, tensile properties, impact strength, and wear resistance have been investigated. According to the findings, the mechanical qualities have significantly improved. The impact fracture toughness of the as-received samples is around 36% lower than the heat-treated alloy in the SAT2 (ST@850 °C/30 min-WQ-ageing@550 °C/120 min-FC) conditions. Ti-6Al-4 V alloy's heat treated on SAT 6 (ST@913 °C/10 min-WQ-ageing@550 °C/90 min-FC) condition has the maximum hardness, which is around 16.62% higher than the as-received alloy. The greatest tensile strength for an alloy is achieved under SAT5 (ST @913 °C/20 min-WQ-ageing @450 °C/120 min-FC) conditions. The specimens thermally treated at SAT4 (ST@882 °C/30 min-WQ-ageing@450 °C/90 min-FC) and SAT6 (ST@913 °C/10 min-WQ-ageing@550 °C/90 min-FC) exhibit the greatest reduction in wear rate. The improved mechanical and wear properties of the specimens were attributed to the equiaxed small grains and bimodal lamellar structure of the alloy's microstructure, which was altered by heat treatment. [ABSTRACT FROM AUTHOR]

The required important properties of cold work tool steels are hardness, wear resistance, suitable toughness and in many cases corrosion resistance. For cold work tool steels, hardness can be well controlled by heat treatment, but steels of the same hardness do not necessarily have similar wear, corrosion resistance or even toughness. These properties are influenced by the chemical composition of the steels and their manufacturing processes. The study is performed on Böhler K390 PM produced by powder metallurgy (PM) process, Böhler K360 ESR made by electro-slag remelting (ESR) methods and Böhler K110 produced conventionally (C). The specimens were heat treated to obtain the same hardness of 61 HRC. It was made a comparative test of the abrasive wear resistance, corrosion resistance and toughness of the heat-treated cold work tool steel test specimens. The comparative test results show that the Böhler K110 steel has the best corrosion resistance against the 20% acetic acid, and the Böhler K390 PM steel has the best wear resistance and toughness. The goal of the research was to find the optimal cold work tool steel quality for special applications (as a function of wear resistance, corrosion resistance and toughness). The K390 reached the best wear resistance which is two times better than the K360 and about ten times better than the K110. About the corrosion test results, it can be concluded that K110 showed the lowest weight loss after the corrosion test, and the K390 and K360 showed higher weight loss and lower corrosion resistance. Impact energy values from the Charpy impact test were the highest in the case of K390 followed by the K360 and the K110. The results were confirmed by the microscopic analysis.

This research aims to study the wear behavior that occurs with hot forging dies caused by the influence of the work piece’s temperature, the die’s temperature, and the coefficient of friction. The material of the die used in this study was steel with JIS standards and SKD61 Grade. The material of the workpiece was 5CM435 Grade. The default size of the workpiece and production factors were calculated and analyzed by using the Finite Element Method. The study was started by simulating workpiece forging at 850 degrees Celsius, 950 degrees Celsius, 1000 degrees Celsius, 1150 degrees Celsius, and 1250 degrees Celsius for analyzing the workpiece’s flow and wear behavior of the die’s surface under forging pressure of 400 tons with a die temperature from 120 degrees Celsius to 180 degrees Celsius. The results of the analysis revealed that the die’s temperature at 692.41 degrees Celsius and the workpiece’s temperature at 1,250 degrees Celsius yielded the most absolute workpiece flow. The absolute default size of a cylindrical workpiece had a diameter of 13 millimeters with a length of 155 millimeters and the workpiece’s temperature was set at 850 degrees Celsius. Abrasive wear occurred with the die’s lower surface at the highest level. At 1,000 degrees Celsius, plastic deformation occurred at the die’s lower surface. Stress occurred when the workpiece was in the scope of the graph on fracture criteria. From computer simulation forging, It indicated that appropriate adjustment of variables helped to reduce plastic deformation and mechanical fatigue.

The aim of the present study is to investigate the effect of accumulative roll bonding (ARB) and precipitation hardening on the microstructure development and there of mechanical properties of ultrafine grained Al–Ag-Sc alloy. For this purpose, the samples were heated to a temperature of 600 °C for 24 h, and then they were quenched in water. In order to carry out the two-stage precipitation hardening process, the samples were placed in the furnace at a temperature of 350 °C for 5000 s in the first stage, which was followed by quenching in water. In the second stage, they were heated to 250 °C for 5000 s following by water quenching too. Following, the samples were subjected to the ARB for up to 8 cycles. Scanning Electron Microscope (SEM) equipped with Electron Backscatter Diffraction (EBSD) and energy dispersive spectroscopy (EDS) techniques, and X-Ray Diffraction (XRD) was used to verify the microstructure and phase analysis of the prepared samples. Also, tensile and microhardness tests were conducted to confirm the mechanical properties, and pin-on-disk tests were done to check wear behavior. Microstructural parameters such as crystallite size, microstrain, and density of dislocations in rolled sheets were estimated using the Rietveld method. The Results have shown that applying various cycles of the ARB process leads to the development of ultra/nano grain structure. In that sense, performing 8-cycle of the ARB transformed the low angle grain boundaries (LAGBs) of the 4-cycle ARB condition to high angle grain boundaries (HAGBs). Results showed that there is proper welding between different layers, except for the layers created in the last cycle. Similarly, the obtained size of the crystallites demonstrates that the samples become finer when ARB cycles are increased. The results of the mechanical tests indicated that after 8 cycles, there is approximately 3.5-fold and 2.5-fold increase in the tensile strength and hardness compared to the original (annealed) sample, respectively. While the elongation decreased slowly and reached 1.5% in the 8th cycle. A fractography of the fracture surface of the original sample included deep and coaxial dimples, indicating a ductile fracture. Analysis of wear surface degradation showed that scratch wear occurred for all samples.

The primary aim of this study was to determine the influence of CuO-decorated graphene oxide nanoplatelets (CuO@GONPs) loading (0.05, 0.1, 0.3, 0.5, and 0.7 wt.%) on the flexural and wear properties of epoxy-matrix nanocomposites. It is worth noting that the Copper (II) chloride (CuCl2) was used as a nano-CuO generator on the surface of the GONPs in the presence of NaOH. Various analyses such as X-ray diffraction (XRD), Atomic-force microscopy (AFM), Raman spectra, and energy dispersive X-ray (EDX) confirmed the successful synthesizing of the CuO@GONPs hybrid. The results of the flexural tests revealed that the highest obtained flexural strength and flexural modulus belonged to the specimens containing 0.3 wt.% and 0.5 wt.% CuO@GONPs, with 51.8% and 21.3% enhancements respectively, as compared to the neat epoxy. The wear test results showed that adding 0.5 wt.% CuO@GONPs into the epoxy matrix was caused to decrease the wear rate and friction coefficient by 87.4% and 29.6%, respectively. Additionally, the CuO@GONPs/epoxy nanocomposite denoted better flexural and wear behaviors than the pristine GONPs/epoxy one. Overall, the controlled introduction of the CuO@GONPs hybrid into the epoxy matrix was found to be an effective strategy for enhancing its flexural and wear properties. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The required important properties of cold work tool steels are hardness, wear resistance, suitable toughness and in many cases corrosion resistance. For cold work tool steels, hardness can be well controlled by heat treatment, but steels of the same hardness do not necessarily have similar wear, corrosion resistance or even toughness. These properties are influenced by the chemical composition of the steels and their manufacturing processes. The study is performed on Böhler k390 PM produced by powder metallurgy (PM) process, Böhler k360 EsR made by electro-slag remelting (EsR) methods and Böhler k110 produced conventionally (C). The specimens were heat treated to obtain the same hardness of 61 hRC. It was made a comparative test of the abrasive wear resistance, corrosion resistance and toughness of the heat-treated cold work tool steel test specimens. The comparative test results show that the Böhler k110 steel has the best corrosion resistance against the 20% acetic acid, and the Böhler k390 PM steel has the best wear resistance and toughness. The goal of the research was to find the optimal cold work tool steel quality for special applications (as a function of wear resistance, corrosion resistance and toughness). The k390 reached the best wear resistance which is two times better than the k360 and about ten times better than the k110. About the corrosion test results, it can be concluded that k110 showed the lowest weight loss after the corrosion test, and the k390 and k360 showed higher weight loss and lower corrosion resistance. Impact energy values from the Charpy impact test were the highest in the case of k390 followed by the k360 and the k110. The results were confirmed by the microscopic analysis. [ABSTRACT FROM AUTHOR]

This research aims to study the wear behavior that occurs with hot forging dies caused by the influence of the work piece's temperature, the die's temperature, and the coefficient of friction. The material of the die used in this study was steel with JIS standards and SKD61 Grade. The material of the workpiece was 5CM435 Grade. The default size of the workpiece and production factors were calculated and analyzed by using the Finite Element Method. The study was started by simulating workpiece forging at 850 degrees Celsius, 950 degrees Celsius, 1000 degrees Celsius, 1150 degrees Celsius, and 1250 degrees Celsius for analyzing the workpiece's flow and wear behavior of the die's surface under forging pressure of 400 tons with a die temperature from 120 degrees Celsius to 180 degrees Celsius. The results of the analysis revealed that the die's temperature at 692.41 degrees Celsius and the workpiece's temperature at 1,250 degrees Celsius yielded the most absolute workpiece flow. The absolute default size of a cylindrical workpiece had a diameter of 13 millimeters with a length of 155 millimeters and the workpiece's temperature was set at 850 degrees Celsius. Abrasive wear occurred with the die's lower surface at the highest level. At 1,000 degrees Celsius, plastic deformation occurred at the die's lower surface. Stress occurred when the workpiece was in the scope of the graph on fracture criteria. From computer simulation forging, It indicated that appropriate adjustment of variables helped to reduce plastic deformation and mechanical fatigue. [ABSTRACT FROM AUTHOR]

304 stainless steel (304SS) powder and novel Mo-cladded 304SS (304SS-Mo) powder were used as feedstocks to prepare metallic coatings with different inter-splat bonding qualities. Wear test was conducted to examine the dependence of wear behavior on the inter-splat bonding quality. The results showed that poor inter-splat bonding leads to much lower wear resistance in conventional 304SS coating relative to that of 304SS bulk, especially at high loading conditions (>75 N), where the wear rate increased to 5.53 × 10−3 mm3/(m⋅N) by 3.5 times higher than that at low-load range. However, the novel 304SS-Mo coating with metallurgical inter-splat bonding and minimized oxide inclusions exhibited a low wear rate comparable to that of 304SS bulk. Failure analysis of worn samples suggests that splat delamination contributes to low wear resistance of the 304SS coating; conversely, the absence of splat delamination results in higher wear resistance of the 304SS-Mo coating. Using Mo-cladded powders, significantly enhanced inter-splat bonding enables the use of plasma-sprayed metallic coating under high-load wear conditions. The strong dependence of wear resistance on the load in conventional coating implies that evaluation of wear performance of thermally sprayed metallic coating should consider both the wear rate and critical load. [ABSTRACT FROM AUTHOR]

The study investigates the mechanical properties of dual-phase (DP) steel undergoing surface martensite transformation through Surface Mechanical Attrition Treatment, revealing phase transformation and grain refinement, increasing exponentially with treatment duration. After 40 min of SMAT, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses revealed approximately 37% martensite and 63% ferrite phases, in contrast to 5% martensite and 95% ferrite phases in the as-received state. The surface hardness of the steel increased to 270 VH0.05 (up from 145 VH0.05), while the yield strength rose to 405 MPa (up from 258 MPa). Furthermore, a 60% reduction in the specific wear rate of the steel was achieved. This study highlights SMAT as an innovative method for tailoring the microstructure of steel and enhancing its mechanical properties through stress-induced phase transformation.

Nickel–Copper alloys hybrid composite was formed in an induction furnace set up on a sand substrate. With different percentages of Al2O3 (3, 6, 9 and 12 wt%) and TiO2 (constant 9 wt%) reinforcements, the goal is to examine the wear behavior and friction coefficient of Ni–TiO2–Al2O3. The factors considered for the wear analysis were sliding distance (1500, 1000, and 500 m), applied load (25, 50, and 75 N), and sliding velocity (1.46, 2.93, and 4.39 m/s). The pin-on-disc equipment is utilized to perform different wear tests are carried out using in accordance with the Taguchi L27 orthogonal array. The machine learning used to correlate between actual and anticipated values for both metrics is strong, with a reasonable error margin. The Mean Squared Error (MSE) for the wear rate was 0.1025 (10.25%) in the Linear Regression model and 0.2390 (23.89%) in the Random Forest model. Regression analysis determined the impact of several parameters on wear rate, whilst machine learning approaches expanded the evaluation of wear rate and coefficient of friction beyond experimental data. The findings demonstrate the effectiveness of combining Taguchi methods with machine learning to accurately anticipate wear mechanisms in Ni–Cu alloy composites.

Titanium (Ti) alloys have been widely used in biomedical applications due to their superior mechanical, physical, and surface properties, while improving their tribological properties is critical to widening their biomedical applications in the current era. The present review examines the recent progress made in enhancing the tribological performance of titanium alloys and titanium matrix composites for biomedical purposes. It specifically focuses on the progress made in biomedical coatings, mechanical surface treatment, and developing titanium matrix composites in terms of their processing, tribological testing conditions, and characterization. Despite thorough investigations, the specific testing procedures for evaluating the friction and wear properties of the alloy and/or biomedical component are still uncertain. The majority of researchers have selected test methods and parameters based on previous studies or their own knowledge, but there is a scarcity of studies that incorporate limb-specific tribological tests that consider the distinct kinematic and biological structure of human limbs. Since advanced microscopy has great potential in this field, a variety of advanced characterization techniques have been used to reveal the relationship between microstructural and tribological properties. Many coating-based strategies have been developed using anodizing, PEO, VD, PVD, nitriding, thermal spray, sol-gel, and laser cladding, however; composition and processing parameters are crucial to improving tribological behaviour. Reinforcing component type, amount, and distribution has dominated Ti matrix composite research. Ti grade 2 and Ti6Al4V alloy has been the most widely used matrix, while various reinforcements, including TiC, Al2O3, TiB, hydroxyapatite, Si3N4, NbC, ZrO2 have been incorporated to enhance tribological performance of Ti matrix. Mechanical surface treatments improve biomedical Ti alloys’ tribological performance, which is advantageous due to their ease of application. The implementation of machine learning methods, such as artificial neural networks, regression, and fuzzy logic, is anticipated to make a substantial contribution to the field due to their ability to provide cost-effective and accurate results. The microstructural and surface features of biomedical Ti alloys directly affect their tribological properties, so image processing strategies using deep learning can help researchers optimize these properties for optimal performance.

The wear behavior of SiC bonded diamond materials produced by liquid silicon infiltration in diamond preforms was investigated. The wear behavior in sand blasting tests (SiC abrasives, 5 bar pressure) was correlated with the microstructure. All SiC bonded diamond materials showed a wear, which was approximately 10 times less than the wear behavior of the reference SiC material.Systematic changed microstructures were created by increasing the infiltration temperature. As the infiltration temperature increases, a graphite layer is formed at the diamond-SiC interface. At the highest infiltration temperature (1670 °C), the layer thickness reaches approx. 580 nm. The results show that wear resistance is not negatively affected by the graphite layer. On the contrary, for materials with a graphite layer thickness of up to 70 nm, the wear resistance increases by up to 30 %. The wear increases again only at the highest infiltration temperature. However, this is probably caused more by the internal damage to the diamonds and not by the graphite layer at the interface.

The current trend of increasing the precision lifetime of high-performance bearings forces scientists and engineers to optimize the heat treatment and processing technology to endure higher fatigue frequencies from rolling/sliding motion. In this study, the influences of two crucial factors, hardness and spherical carbides, on the wear behavior of AISI 52100 bearing steel were investigated using elaborate heat treatments to control the variables. The results showed that avoiding excessive hardness and improving the content of spherical carbides could reduce the wear volume during sliding friction and enhance wear resistance. On the one hand, high hardness is correlated to high carbon concentration and high micro-plastic strain in the martensite matrix, inducing the propagation of microcracks and formation of large-size shallow micro-pitting, which accelerates wear loss. On the other hand, spherical carbides effectively inhibit severe plastic deformation of the martensite matrix, which inhibits the wear loss caused by micro-cutting and decreases the formation of wear debris. In this case, densely distributed carbides can improve the wear performance.

In this research, Friction Stir Additive Manufacturing (FSAM) has been investigated for the production of AA6061/TiC-graphene hybrid nanocomposites. For this purpose, nanocomposites were produced in the shape of three-layer cylindrical parts by Friction Stir Deposition (FSD) of the AA6061 consumable rod with pre-placed reinforcement nanoparticles in it (0.25 wt%). TiC and graphene nanoparticles were chosen as the reinforcements for improving hardness and wear behavior in the additive manufactured parts, respectively. The nanocomposites were deposited with four different rotation speeds, including 1200, 1300, 1400, and 1500 rpm, under a continuous feeding speed of 25 mm/min. Also, a reference sample without any reinforcement was deposited for comparison with the nanocomposites. Appearance characteristics, microstructural specifications, hardness, wear behavior, and corrosion resistance were investigated for evaluation of the manufactured parts. FSAM led to the production of fine-grain nanocomposites (∼15–25 μm) with a relatively uniform distribution of the reinforcement nanoparticles. The addition of reinforcement nanoparticles caused improvements in hardness, wear rate, friction coefficient, and corrosion rate by about 42%, 66%, 15%, and 33%, respectively. In this regard, best-manufactured nanocomposite showed good hardness (71.5 HV), superb wear rate (260 × 10^-5 mg/N.m), low friction coefficient (0.697), and excellent corrosion rate (2.6 mpy). Finally, it was observed that performing FSD by increasing the tool rotation speed at a constant vertical speed resulted in nearly 10% grain growth and 45% dissolution of Mg-rich precipitates in the matrix. These microstructural evolutions decreased hardness (∼24%) and corrosion rate (∼50%), and increased wear rate (∼38%) and friction coefficient (∼16%) in the nanocomposites.

Combustion synthesis (CS) is a well-known technique for manufacturing intermetallic compounds and intermetallic-matrix composite materials. This research focuses on fabricating NiAl-matrix composites with varying TiC/TiB2 contents as reinforcement, achieved by the combustion synthesis method. The chemical reactions that yield the final NiAl–TiC–TiB2 compounds were interpreted using thermodynamic calculations. The phase analysis and morphology of the composites were investigated using X-ray diffractometry (XRD) and scanning electron microscopy (SEM) characterization techniques, respectively. The findings demonstrate that the NiAl matrix contains evenly distributed TiC–TiB2 ceramic-based particles, and no oxidation of reactants occurred during the combustion reaction. With an increase in the TiC–TiB2 reinforcement phases from 0 to 15 wt %, the hardness of the NiAl–TiC–TiB2 product significantly rose from 496 to 1015 Vickers, while the porosity increased from 24% to 39%, attributed to the reduced quantity of melted NiAl available to fill the pores. Examining tribological behavior in synthesized composites involved combining experimental-numerical methods, utilizing sliding wear tests and artificial neural network (ANN) modeling. The wear results revealed decreasing wear rates with reduced loads (from 35 N to 25, and 15 N) and higher TiC/TiB2 ceramic content. Iron traces at C0 and C10 worn samples were 2.47 and 26.18 wt % respectively, which indicates enhanced hardness. The experimental data were used to train and test an artificial neural network (ANN) and statistical analysis revealed a remarkable accuracy of 91% for the ANN model in predicting friction coefficients within SHS-processed composites, as indicated by the R2 value of 0.91 and a MAPE of 6.47.

In order to study the effect of aging strengthening on the wear mechanism and frictional deformation behavior of rare earth magnesium alloys, GW83 (Mg-8Gd-3Y-0.5Zr, mass fraction/%) rare earth magnesium alloy was prepared by extrusion process. The electronic universal testing machine was used to evaluate the alloy's mechanical properties.The optical microscope (OM), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to examine the alloy's microstructure.The ball-on-disc dry sliding friction testing machine was used to examine the wear resistance. The results show that after aging treatment (T5), a large amount of β′ precipitated phases are precipitated in the alloy. The hardness and tensile strength of the alloy are 124.1HV and 420.31 MPa, respectively, which are significantly higher than those in the extruded state (O state). As the load increases, the friction coefficient of the alloy decreases and the wear rate increases. Aging treatment can significantly improve the wear resistance of GW83 alloy, which is related to changes in wear mechanism and degree of friction deformation. Under a load of 5-10 N, the main wear mechanisms of both samples are abrasion, oxidation, and adhesive wear. When the load increases to 20 N, the main wear mechanism of the O state sample changes to delamination wear, while the transition load of the T5 sample is 80 N. T5 heat treatment significantly reduces the degree of surface metal deformation and deformation layer thickness caused by friction, thereby reducing the generation of friction cracks.

In recent decades, batch hot-dip galvanized (HDG) steel has proven itself in practical applications due to the good corrosion resistance of its components. Despite the importance of the mechanical-load-bearing capacity of these coatings, the wear behavior has, so far, only been investigated very sporadically and not systematically, so a quantification of the wear behavior and statements on the mechanisms are vague. Therefore, two body wear tests with bonded abrasive grain were carried out. Varying the friction rolls, load, and total number of cycles, the wear behavior was investigated. The mass loss and the layer thickness reduction were measured at different intervals. After the test, the microstructure in the cross-section and the hardness according to Vickers (0.01 HV) were evaluated. The results showed that the wear behavior of HDG coatings against abrasive loads can be characterized with the selected test conditions. Initially, the applied load removed the soft η-phase. As the total number of cycles increases, the η- and ζ-phases deform plastically, resulting in a lower mass reduction compared to that expected from the measured layer thickness. The characteristic structure of a batch HDG coating with hard intermetallic Zn-Fe phases and an outer pure zinc phase has demonstrated effective resistance to abrasion. [ABSTRACT FROM AUTHOR]

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This study investigates the fabrication, wear characterization, and coefficient of friction (COF) prediction of open-cell AlSn6Cu–Al2O3 composites obtained by a liquid-state processing technique. Focusing on wear behavior under varying loads using the pin-on-disk method, this research characterizes microstructure and phase composition via SEM, EDS, and XRD analyses. A novel aspect of this research is the application of an LSTM recurrent neural network model for the fast and accurate prediction of the COF of the composites, eliminating the need for extensive experimental work. Additionally, feature importance analysis using Random Forest regressors is conducted to ascertain the relative contribution of each input variable to the output variable, enhancing our understanding of the wear mechanisms in these materials. The results demonstrate the effectiveness of the composite's reinforcement in improving wear resistance, highlighting the critical role of mechanical stress and the reinforcement's hardness in the wear process. The quantitative findings related to the wear behavior include a mass-wear reduction in the open-cell AlSn6Cu–Al2O3 composite from 8.05 mg to 1.90 mg at 50 N and a decrease from 17.55 mg to 8.10 mg at 100 N, demonstrating the Al2O3 particles' effectiveness in improving wear resistance under different loads. [ABSTRACT FROM AUTHOR]

Additive manufacturing technologies for metallic materials based on powder bed fusion have enormous industrial potential. In this study, we manufactured 18Ni-300 maraging steel using the powder bed fusion (PBF) process and investigated the effects of annealing temperatures of 430 °C, 490 °C, and 550 °C for 3 h on its microstructure, tensile fracture mechanism, and wear properties compared with the as-built specimen. The results show that annealing heat treatment effectively improved the dry sliding friction, wear properties, and room temperature tensile properties compared to the as-built specimen. Compared to other aging-treated samples, specimens that underwent heat treatment in optimal settings had superior properties. With optimal heat treatment, while melt pool boundaries remained, the cellular and columnar structures became finer compared to the un-treated specimens, and the number of dimples decreased. Consequently, the hardness and tensile strength improved by approximately 56.17% and 40.63%, respectively. The 18Ni-300 maraging steel sample that underwent heat treatment at optimal settings exhibited a coefficient of friction approximately 33.33% lower than the as-built alloy. [ABSTRACT FROM AUTHOR]

A grinding wheel with orderly-micro-grooves is a new type of structured grinding wheel for grinding narrow-deep slots. It can improve the carrying capacity of the coolant in the grinding zone effectively. The wear and evolution of grains directly determine the sharpness of the grinding wheel, and this affects the grinding performance in terms of efficiency, surface integrity, and tool life. In order to design the grinding wheel for minimized wear in its use, this study elucidates the wear behaviors of the grinding wheel with orderly-micro-grooves in grinding narrow-deep slots. Through the comparative experiments of the grinding narrow-deep slot, the impacts of micro-grooves on the wear behaviors of the grinding wheel are evaluated, and the wear behavior of the grains on the cut-in edge, cut-out edge, cylindrical surface, and side surface is observed, respectively. The analysis of the grinding ratio, grinding force, and force ratio further verifies the analysis of the wear mechanism and the grinding performance. It is found that (1) the macro-fracture of grain on the cut-in edge occurred due to the large cutting thickness increasing the load of the grain; (2) the debonding phenomenon reduces the anchoring force of the grain, and this tends to pull out the grain on the cut-out edge; (3) due to the adhesion action of the micro-welds, the main failure behavior of the grain on the cylindrical surface is chip adhesion, and the bridge adhesion appears at the small inter-grain space; (4) grains on the side surface are less engaged in removing workpiece materials, the cutting depths of the grains in the middle and inner zones are ignorable, and attrition wears and micro-fractures occur on the grains on the side surface. The grinding force and force ratio variation further verifies that the grinding wheel with orderly-micro-grooves can achieve self-sharpening to maintain excellent grinding performance. [ABSTRACT FROM AUTHOR]

Several industrial applications make substantial use of the aluminium alloy. The impact of Sr/Na on the microstructure, mechanical properties, and wear mechanics of Al7075 alloy was examined in the current experiment. The findings showed that the microstructure improved by the inclusion of elements (Sr/Na). Uniform dispersion of particles (Sr/Na) and changed structure of silicon (Si) in the Al7075 alloy were noted. Hardness of the developed alloys was checked with micro hardness tester and micrographs were taken using metallurgical microscope. Pin-and-Disc wear test equipment was used to measure the wear rate of the modified alloys. The wear test trials were carried out using the Taguchi technique in order to increase the accuracy of the results. The L27 array was used to evaluate the data. Applying ANOVA (Analysis of Variance) approach, the impact of changing parameters (factors) on wear loss and COF was examined. The obtained result indicates that, hardness and tensile strength increases by 37.78% and 14.57% respectively when compared to the base alloy. It is due to the increase of wt. % Sr modifier. The ANOVA analysis results indicate that, wt. % of Sr is most significant (69.70 %) parameter followed by Na (wt. %), Load (N) & Speed (rpm). The Sr/Na content has a more substantial impact on the wear behaviour and COF of the modified alloy, according to the results of the ANOVA. A worn-out surface's internal fracture structure can be seen in a wear fractography report after SEM analysis. [ABSTRACT FROM AUTHOR]

Resin matrix composites are commonly utilized in water-lubricated stern tube bearings for warship propulsion systems. Low-speed and high-load conditions are significant factors influencing the tribological properties of stern tube bearings. The wear characteristics of resin-based laminated composites (RLCs), resin-based winding composites (RWCs), and resin-based homogeneous polymer (RHP) blocks were investigated under simulated environmental conditions using a ring-on-block wear tester. Simulated seawater was prepared by combining sodium chloride with distilled water. The wetting angle, coefficient of friction (COF), and mass loss were measured and compared. Additionally, their surface morphologies were examined. The results indicate a significant increase in the COFs for the three materials with an increased speed or load under dry conditions. The COF of the RLCs is the lowest, indicating that it has superior self-lubricating properties. In wet conditions, the COFs of the three materials decrease with an increasing speed or load, exhibiting a pronounced hydrodynamic effect. The COF and mass loss of RWCs are the highest, while RLCs and RHP exhibit lower COFs and mass loss values. The reticulated texture and flocculent fibers on the surface of RLC enhance the heat diffusion and improve the material wettability and water storage capacity. The surface of RWC is dense, and the friction area under dry conditions is melted and brightened. The surface of RHP is smooth, while the worn material forms an agglomerate and exhibits susceptibility to burning and blackening under dry conditions. The laminated formation method demonstrates superior tribological performance throughout the wear evolution process.

Recognizing the lightweight nature and superior tribological properties of Al-based metal matrix composites, this study introduces a novel analytical model based on polynomial approximations, offering new insights into the mechanisms of dry friction in AlSi10Mg-SiC composite materials. Key findings highlight a significant reduction in the coefficient of friction (COF) and oscillation amplitudes in SiC-reinforced composites, indicating superior tribological performance compared to their unreinforced counterparts. This behavior is attributed to the effective distribution of SiC particles within the aluminum matrix, which mitigates the stick–slip motion commonly observed under dry sliding conditions. Importantly, the model using polynomial approximations is noted for its simplicity and ease of implementation in practice. The study’s conclusions not only underscore the benefits of SiC reinforcement in enhancing wear resistance but also contribute to the broader field of materials science by providing a robust framework for the predictive modeling of COF in various composite systems.

In the present study, the densification behavior, microstructural evolution, mechanical properties, and friction behavior of a TiB2/Al8SiCu composite and Al8SiCu alloy manufactured by laser powder-bed fusion (PBF-LB) were systematically investigated. The results confirm that the addition of in situ TiB2 particles into Al8SiCu alloys reduce the volumetric energy density required for a high-density TiB2/Al8SiCu composite. The TiB2 particles promoted a transformation of columnar to equiaxed crystals and the formation of high-angle grain boundaries. The grains on the vertical direction of the PBF-LBed TiB2/Al8SiCu composite were much finer than those of the PBF-LBed Al8SiCu alloy. The addition of TiB2 promoted the grain refinement of the Al8SiCu alloy, of which the average grain size decreased from 15.31 μm to 7.34 μm. The yield strength (YS), ultimate tensile strength (UTS), and elongation (El) of the PBF-LBed Al8SiCu alloy were 296 ± 6 MPa, 517 ± 6 MPa, and 11.7 ± 1.0%, respectively. The PBF-LBed TiB2/Al8SiCu composite achieved a balance between strength and ductility with a yield strength of 328 ± 8 MPa, an ultimate tensile strength of 541 ± 3 MPa, and an elongation of 9.1 ± 0.7%. The increase in strength mainly resulted from grain boundary strengthening, dislocation strengthening, load-bearing strengthening, solid-solution strengthening, and Orowan strengthening, of which the dislocation strengthening and Orowan strengthening were critical. The enhanced hardness associated with the grain refinement and the formation of the in situ TiB2 particles also led to an enhanced tribological performance, of which reductions in the average friction coefficient from 0.655 to 0.580 and wear rate from 1.76 × 10−3 mm3/Nm to 1.38 × 10−3 mm3/Nm were found.

ZG25MnCrNiMo steel samples were prepared by squeeze casting under pressure ranging from 0 to 150 MPa. The effects of pressure on the microstructure, low-temperature toughness, hardness, and impact wear performance of the prepared steels were experimentally investigated. The experimental results indicated that the samples fabricated under pressure exhibited finer grains and a significant ferrite content compared to those produced without pressure. Furthermore, the secondary dendrite arm spacing of the sample produced at 150 MPa decreased by 45.3%, and the ferrite content increased by 39.1% in comparison to the unpressurized sample. The low-temperature impact toughness of the steel at −40 °C initially increased and then decreased as the pressure varied from 0 MPa to 150 MPa. And the toughness achieved an optimal value at a pressure of 30 MPa, which was 65.4% greater than that of gravity casting (0 MPa), while the hardness decreased by only 6.17%. With a further increase in pressure, the impact work decreased linearly while the hardness increased slightly. Impact fracture analysis revealed that the fracture of the steel produced without pressure exhibited a quasi-cleavage morphology. The samples prepared by squeeze casting under 30 MPa still exhibited a large number of fine dimples even at −40 °C, indicative of ductile fracture. In addition, the impact wear performance of the steels displayed a trend of initially decreasing and subsequently increasing across the pressure range of 0–150 MPa. The wear resistance of samples prepared without pressure and at 30 MPa was superior to that at 60 MPa, and the wear resistance deteriorated when the pressure increased to 60 MPa, after which it exhibited an upward trend as the pressure continued to rise. The wear mechanisms of the samples predominantly consisted of impact wear, adhesive wear, and minimal abrasive wear, along with notable occurrences of plastic removal, furrows, and spalling.

In this study, ceramic particle (WC) reinforced AlCoCrFeNi 2.1 eutectic high entropy matrix composites (WC x /HEA 1-x , x = 0, 5, 10 wt%) were prepared by using laser powder bed fusion (LPBF) technology. The microstructure evolution and wear behavior of the printed WC x /HEA 1-x composites were analyzed, and the strengthening mechanism and anti-wear mechanism of the WC x /HEA 1-x composites were extensively studied. The results show that the reinforcement ceramic particles (WC) were uniformly distributed in the HEA matrix and a good metallurgical bonding layer between the reinforced phase WC and the HEA matrix were found. The maximum width of the bonding layer is about 330 nm. Under the strong irradiation of high-energy laser, WC was decomposed into W and C elements, and diffused into the HEA matrix. Its reaction with Co, Fe, Ni elements produced M x C (M = Co, Fe, Ni) carbides. Part of W and C elements were soluble in the HEA. The wear resistance of the printed composite is found affected by the content of added ceramic particle (WC). The ranking of the wear resistance of the printed composites was found to be WC 0.05 /HEA 0.95 > HEA ≈ WC 0.10 /HEA 0.90. The improvement of wear resistance by adding WC was found due to interfacial load transfer strengthening of WC particles, solution strengthening of W and C atoms; and the second phase strengthening of various carbides M x C (M = Co, Fe, Ni). [ABSTRACT FROM AUTHOR]

Ceramic matrix composites (CMCs) have become important structural materials of aero-engines under elevated operating temperature while the abradable ceramic coatings matched with CMCs are seldom reported. In this work, the atmospheric plasma spray (APS) technique was used to fabricate and design Yb2Si2O7-based coatings with various contents of CaF2. The phase composition and microstructure of the coatings, as well as Rockwell hardness, were characterized. The wear and abradable behaviors of the coatings including friction coefficients and volume wear rates were evaluated at room temperature and 900 °C, respectively. The results show that the Rockwell hardness and friction coefficients decreased, and the volume wear rates of the coatings at room temperature significantly raised with the increase of CaF2 content. The coatings exhibited quite different behaviors at 900 °C compared with those at room temperature owing to the lubricant effect of CaF2. The morphologies of the coatings after the wear tests were characterized and the possible failure mechanisms were analyzed, and this study may provide guidelines for the application of the abradable coatings suitable for CMCs. [ABSTRACT FROM AUTHOR]

Herein, Nb element is introduced into the AlCoCrFeNi2.1 eutectic high‐entropy alloy to create a heterogeneous structure. AlCoCrFeNi2.1Nbx (x = 0, 0.25, 0.5) eutectic high‐entropy alloys (HEAs) are fabricated using selective laser melting technology. The forming characteristics, microstructure, and mechanical properties of the AlCoCrFeNi2.1Nbx eutectic HEAs are investigated. The results show that the relative density of the samples increase and then decrease. The optimal process parameters are determined as laser power of 50 W, scanning speed of 400 mm s−1, scanning spacing of 70 μm, and layer thickness of 30 μm. The primary microstructure of AlCoCrFeNi2.1Nbx alloys (x > 0) consists of a hypoeutectic structure comprising body‐centered cubic, face‐centered cubic, and Fe2Nb‐type Laves phases. With the addition of Nb element, the hardness of the high‐entropy alloy increases from 600.6 to 774 HV, the yield strength increases from 664.1 to 1091.9 MPa, while the ductility slightly decreases. Furthermore, the strengthening mechanisms of the alloy are attributed to the precipitation strengthening and solid solution strengthening of the Laves phase, as well as the grain refinement effect. The wear resistance of the alloy improves gradually with the increasing Nb content, and AlCoCrFeNi2.1Nb0.5 exhibits the best wear resistance, primarily through adhesive wear. [ABSTRACT FROM AUTHOR]

In this study, the effect of adding SiC nanoparticles and heat treatment on the mechanical properties and wear behavior of A380 aluminum alloy was investigated. Al A380 aluminum powder and SiC nanoparticles with values (0, 0.5, 1, and 2% wt%) were milled in a planetary ball mill with balls of different diameters (4–10 mm) in an argon atmosphere for 10 hours. After the milling process, a hot press (510°C) was used to produce the samples. The microstructure, mechanical properties, and wear behavior of the samples were examined using an optical and scanning electron microscope (SEM), micro Vickers hardness test, and pin-on-disk test, respectively. To investigate the effect of heat treatment, the samples were placed in a furnace at 530°C for 3 hours, then the sample was quenched with boiling water, then placed in a furnace at 175°C for 16 hours, and then by micro Vickers hardness device, the hardness of the samples were measured. The best hardness of the samples was related to aluminum alloy with 0.5 wt% of SiC nanoparticles. Also, after heat treatment, the hardness of the samples increased significantly. Al A380 2wt% SiC nanocomposite sample represents the greatest wear properties when compared with the other experiment samples. [ABSTRACT FROM AUTHOR]

The double-layer NiCr-Cr3C2/Ni-Zn-Al2O3 coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates. The intermediate layers Ni-Zn-Al2O3 were fabricated by using low-pressure cold spray (LPCS) method to improve the salt fog corrosion resistance properties of the supersonic plasma spray (SPS) NiCr-Cr3C2 coatings. The friction and wear performance for the double-layer and single-layer NiCr-Cr3C2 coatings were carried out by line-contact reciprocating sliding, respectively. Combined with the coating surface analysis techniques, the effect of the salt fog corrosion on the tribological properties of the double-layer coatings was studied. The results showed that the double-layer coatings exhibited better wear resistance than that of the single-layer coatings, due to the better corrosion resistance of the intermediate layer; the wear mass losses of the double-layer coatings was reduced by 70% than that of the single layer coatings and the wear mechanism of coatings after salt fog corrosion conditions is mainly corrosion wear. [ABSTRACT FROM AUTHOR]

The purpose of this research was to enhance the wear behavior and hardness of cold work D5 tool steel by depositing a TiCrN multilayer nanocoating through the physical vapor deposition with a cathodic arc. A comparison was made between the properties of the applied coatings and the thin-film TiN and CrN nanolayer coatings produced using the same method. Various tests, including micro-hardness tests, surface wear tests, and corrosion examinations using the Tafel test, were conducted. The coating surfaces and the wear lines were analyzed using field emission scanning electron microscopy with energy dispersive X-ray spectroscopy. The results indicated that the TiN thin-film coating, the TiCrN multilayer nanocoating and the CrN coating exhibited higher hardness of 226, 205, and 165 HV, respectively than the less coated sample (101 HV). Additionally, friction coefficients were measured and found to be 0.35, 0.3, and 0.27 for TiN, TiCrN, and CrN coatings, respectively. Furthermore, the corrosion test results demonstrated that the TiCrN multilayer coating exhibited excellent corrosion resistance. The analysis of wear surfaces revealed abrasion wear mechanisms for the TiN and CrN coatings, while fatigue wear mechanisms were observed for the TiCrN coating. Those findings suggest that the TiCrN multilayer nanocoating has potential applications in the production of tool steel pieces, complementary parts, and machine tool components. [ABSTRACT FROM AUTHOR]