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This study investigated the effect of carbide precipitation hardening of heat-treated SK5M steel on the sliding wear resistance. The cold rolled carbon steel strip samples (J, G, and S-type) were oil quenched after tempering for optimal durations. The wear resistance was evaluated using a pin-on-disk wear test with an alumina counterface against different samples at various loads and distances with a constant running speed. The size and distribution of the precipitated carbides were observed using an image analyzer at various heat treatments. The heat-treated samples presented more dense carbide distribution in an area fraction and the decreased size of carbides. It is confirmed that the wear rate is minimum at an optimized austenitizing temperature of around 800°C. The specific wear rate indicates that the S-type sample has high wear resistance compared to that of J-Type. This is understood by stable wear behavior of S-type sample containing evenly distributed carbide precipitation.

In this research, Cu-9Pb high leaded bronze were prepared by spray forming. The microstructure and wear properties of this bronze alloy were systematically investigated. The results show that although the hardness of spray formed alloy was not increased comparing with the cast alloy, it still presented a lower wear rate and a lower friction coefficient in dry sliding wear tests as shallower grooves and more lubricating films were observed in the spray formed bronze (BSF14). Spray forming also refined the lead phase microstructure of Cu-9Pb bronze and improved its wear properties.

Recently, the wear properties of high-leaded tin bronze were greatly concerned. In this work, the effect of size refinement and distribution of the lubricating lead phases in the spray forming (SF) high-leaded tin bronze on wear rates was studied by using scanning electron microscopy and sliding adhesive wear tests. It was observed that compared to the conventional casting bronze, the SF bronze features finer and more dispersed lead phases that formed more lubricating films in microstructure, which leads to the less wear rates.

In this work, plasma electrolytic oxidation (PEO) ceramic coatings were prepared on magnesium AZ31B alloy. Various electrolyte solutions including phosphate, aluminate and silicate as additives and NaOH $+$ Na₂SiF₆ as constant agent were used to prepare the coatings. Influence of the additives on chemical composition and structure of the PEO coatings were examined by means of scanning electron microscope (SEM) and XRD. From structural analysis it was found that coatings prepared in the aluminate-based electrolyte have the best structural features. Microhardness and tribological characteristics of the PEO coatings were investigated using Vickers hardness test and pin-on-disc test. Microhardness for aluminate-based coating was found to be 1169.63HV while those for silicate-and phosphate-based coatings were 1093.42HV and 285.91HV, respectively. Wear rate of the aluminate-based coating was found to be lowest than all other coatings having a value of $2.78\times 10^{-3}$mg/Nm.

This study explored the friction and wear behavior of a Ni-based exhaust valve at high temperatures. Nickel-based superalloy was used with two types of processing states: the original forged sample and the sample under the standard T1 heat treatment. At room temperature and a loading force of 10N, the average friction coefficient of the T1 heat-treated specimen is 0.61, which was lower than that of the forged sample (0.78). The wear rate of this specimen was also lower than that of the forged sample at the same temperature and loading force. Thus, T1 heat treatment can significantly improve the wear resistance of the alloy because of ${\gamma }^{\prime }$ phase and carbides. The wear rate was the minimum at 550^∘C and increased again at 750^∘C dominated by the formation and flake-off of the oxide film.

This paper presents the tribological examination of various percentages of montmorillonite nanoclay-filled polyester composites and jute fiber reinforced hybrid composites by the Pin on Disc wear testing method. The wear rate and coefficient of friction were investigated for each composition with the working parameters like applied load (10,20,30N), sliding speed (3m/s), and sliding distance (1500m). The reduction in the wear rate was found on the inclusion of 5wt.% clay and 25wt.% jute fiber and further addition of fiber changes the trend due to the reduced matrix concentration. The wear mechanism of the worn-out surface samples was studied using scanning electron microscopy.

In the present era, aluminum-based metal matrix composites, commonly known as aluminum matrix composites (AMCs), play a crucial role in fabricating lighter weight components in the aerospace, automotive, aircraft and marine industries. Intensive research is required to fabricate AMCs economically. In this recent research, AA7068–ZrB₂ AMCs were successfully produced using the in-situ method of fabrication. The inorganic salts such as K₂ZrF₆ and KBF₄ reacted with molten aluminum at 850^∘C and formed ZrB₂ particles in the aluminum melt itself. The castings of AA7068–ZrB₂ AMCs were obtained with 0, 3, 6 and 9 volume fractions (vol.%) of ZrB₂in-situ particles. The pin-on-disc wear apparatus was used to conduct the dry sliding wear analysis of AA7068–ZrB₂in-situ AMCs. The wear experiments were conducted in line with the Design of Experiments (DoE). An orthogonal array of $L_{16}$ was employed for the DoE. The effects of wear parameters such as vol.% of ZrB₂ particles, sliding speed, sliding distance and normal load on the wear rate (WR) and coefficient of friction (COF) were observed. The effects of individual parameters on the WR and COF were observed by contour plot, residual plot and Analysis of Variance (ANOVA). The worn surfaces of AA7068–ZrB₂ (0, 3, 6 and 9 vol.%) AMCs were also observed using the field-emission scanning electron microscopy (FESEM).

Plates of AZ31B were friction stir processed in three different environments, such as liquid nitrogen, water and air with a rotational speed of 1200rpm and feed rate of 90mm/min. Microstructural studies were carried out using optical and electron microscopes, phase identification was performed using X-ray diffraction, and all specimens were tested for hardness, tensile and wear. An examination of wear debris morphology was carried out. Under cryogenic, water and air mediums, grain refinement was achieved at 1.89, 2.23 and 18.23μm, respectively. The specimen using cryogenic medium displayed greater tensile strength and elongation than the water medium. Dissolution of consistently refined grains and secondary Mg₁₇ Al₁₂ particles was observed after FSP underwater and cryogenic medium, resulting in a significant increase in microhardness. This surface hardening produced a significant benefit for the friction and wear behavior of the magnesium as measured by pin-on-disc configuration using a universal tribometer. With a cryogenic cooling medium, the friction coefficient is reduced by approximately 23% and the wear rate is reduced by 8% in comparison to AFSP.

Friction stir processing (FSP), which was the advancement in the friction stir welding technique, is thought to be an economic approach to alloying in the solid state that can be used to make composites. In this study, FSP was carried out to produce AA7075 (B₄$\mathrm{\text{C}}+\mathrm{\text{T}}$iN) composite by varying the composition of the reinforcement particles. Microstructural analysis was carried out and the homogenous distribution of the reinforced particles on the surface of AA7075 alloy was ensured. X-ray diffraction studies were carried out to analyze the phases present after fabricating the hybrid surface composites. Microhardness test was performed on the specimens before and after the fabrication process. Grain refinement in the friction stir processed zones was evidently seen in the optical microstructures. The combined effect of the ceramic powders and grain refinement led to increase in the microhardness in the hybrid surface composites compared with the base AA7075 plate. A 33.87% increase in microhardness was observed in the sample AA7075 reinforced with 75% B₄C and 25% TiN. Wear testing was carried out at various loads (5, 10, 15 and 20 N) and at different sliding velocities (300, 350, 400 and 450 rpm) and the track distance was maintained at 1000 m. It was observed that the highest wear rate is $3.2\times 10^{-7}$ cm³/Nm for the base plate AA7075 and the sample AA7075 reinforced with 50% B₄C and 50% TiN shows the lowest wear rate of $0.56\times 10^{-7}$ cm³/Nm. It is observed that the addition of B₄C and TiN has resulted in a significant improvement in the wear resistance of the AA7075 alloy.

In this study, liquid casting process is used to fabricate AA1050/SiC composites. To increase the wettability of molten Al and improve the adhesion of particles to metallic matrix, liquid casting was selected as the fabrication process. AA1050 and Nano-SiC particles were selected as metallic matrix and reinforcements, respectively. Then, wear, mechanical properties, fracture toughness and forming limit diagram of (FLD) of aluminum composite samples have been investigated experimentally. To do this, AA1050/SiC composite strips with thickness of 1 mm have been fabricated up to eight ARB passes at 300^∘C. The graining was investigated via optical microscopy (OM). The ultimate tensile strength (UTS) of samples improved to 170 MPa registering 168% improvement than the initial monolithic sample. Also, the bonding quality among the layers improved by decreasing the thickness of layers at higher number of passes (increasing the plastic strain). SEM fracture surface morphology of samples after the tensile test showed that by increasing the ARB passes, shear ductile was the fracture mode. So, deep dimples are shrinking slowly relative to the annealed sample. The FLDs’ area dropped sharply for pass 1 and then improved at higher passes as the criterion of formability. Also, wear resistance of composite samples was better than monolithic sample. Moreover, at the 10th pass, the fracture toughness enhanced to the maximum value of 33.5 MPam${}^{1/2}$.

The aim of this study is to provide insights into the performance of copper-based brake pads used in high-speed trains and contribute to a more predictable braking system by leveraging mathematical and artificial intelligence (AI) models. The wear behavior of Cu-based brake pads in high-speed trains was investigated using a pin-on-disc test setup under different speeds, temperatures, and loads with a constant sliding distance. Additionally, mathematical and AI models were developed to predict the friction coefficient and wear rate values obtained from the experiments. This innovative approach initiates a significant discussion in line with a current need, and the sharing and publication of the obtained results are currently essential to address the knowledge gap in this field. The results revealed that an increase in temperature led to an increase in both the friction coefficient and wear rate. Conversely, an increase in load resulted in a decrease in both the friction coefficient and wear rate. The transition from abrasive wear to adhesive wear occurred due to the softening of copper between friction surfaces, leading to material transfer. According to the results obtained from the models, both the artificial neural network (ANN) and multiple regression models demonstrated comparable accuracy, predicting the friction coefficient with approximately 94% accuracy in both cases, indicating reliable predictions. For the wear rate, the models achieved approximately 90% and 92% accuracy, respectively.

Composite materials are combinations of distinct materials, engineered to create new materials with specific properties. Stir-casting method is used to prepare composites, it involves heating Aluminium Alloy (Al 8011) reinforced with B₄C (Boron Carbide) and fly ash at 5, 10, and 15vol.%. The molten material is poured into a die to prepare the samples for testing. The composite’s density is measured by the principle of Archimedes, which decreases as the reinforcing particles increase, and then density and porosity are compared. The wear test specimen was prepared as per standard. The design model is generated by applying the RSM (Response Surface Methodology) equation with various parameters like load, sliding velocity of the pin, and track distance with values of 1–2kg, 1.5–2.5m/s, and 1000–3000m, respectively. The developed ANOVA (Analysis of Variance) result suggests that the created model is significant. The validation test was run and the results showed mean value of 0.0021356 and this value is in the 95% prediction range. The SEM (Scanning Electron Microscope) images of wear-tested composite show the delamination layers and deep groves. EDS (Energy Dispersive Spectroscopy) is used with electron microscopes to determine the chemical composition of wear out specimens. By the end of this study, it is discovered that the wear rate lowers with increasing reinforcement percentage while increasing with load and sliding velocity.

This research aims to study the addition of nanoclays on unsaturated polyester (UP) and epoxy resin (EP) as filling and by weight percentage (2%, 4% and 6%) to this mixture and then study the extent of the effect of this addition on wear rate of the composites’ material where three loads were adopted (10, 15 and 20N), respectively, on the iron hard disk (269 HB) and copper hard disk of 111HB for the resin before and after adding the clays, where the approved sliding velocities were 4.1887, 3.1415 and 2.0943m/sec, respectively, and the test duration was 10 min on the test disc. Immersion of samples in the water for 2, 4, 6 and 8 weeks showed a clear improvement in the wear rate and tear values of dry and submerged conditions in a water under different conditions of load change, slipping speed, time and temperature stability after adding the nanoclays to the polymer.

The present study considers the tribological behavior and corrosion resistance of electroless Ni-B-W coatings deposited on AISI 1040 steel substrates. Coating is characterized using scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction technique. In as-deposited condition, coatings are found to be amorphous. On heat treatment, precipitation of crystalline Ni (1 1 1) and its borides take place. For as-deposited coating, the microhardness is obtained as $\sim$759HV${}_{100}$ which increases to $\sim$1181HV${}_{100}$ and $\sim$1098HV${}_{100}$ when heat treated at 350${}^{\circ }$C and 450${}^{\circ }$C, respectively. Incorporation of W in Ni-B coating results in an increase of hardness by 89HV${}_{100}$ in as-deposited condition. Heat treatment also results in increase in crystallite size of Ni (1 1 1). Wear rate and coefficient of friction (COF) of the coatings are evaluated on a pin-on-disc setup under both dry and lubricated sliding conditions. Wear resistance is observed to improve on heat treatment with an increase in crystallite size while COF deteriorates. However, in as-deposited condition, wear rate and COF of Ni-B-W coatings improve by $\sim$5 and $\sim$3 times, respectively, compared with Ni-B coatings. Wear and friction performance of the coatings are enhanced under lubrication due to the columnar structure of the coatings that retain lubricants. Corrosion resistance of Ni-B-W coating in 3.5% NaCl solution gets improved on heat treatment.

A numerical approach was proposed to investigate the wear behavior occurred in the artificial hip joints in this paper. In the numerical simulations, the wear coefficients taken from pin-on-disk tests were introduced into the wear analysis model to assess the wear rates of polyethylene acetabular cups against metallic or ceramic femoral heads. For the established material combinations, different values of polyethylene wear rates were obtained respectively, which were not necessarily the realistic one as expected in vivo but could be confirmed after further discussion on the wear mechanism involved in wear tests. Current results indicated that the polyethylene/ceramic couples represented better wear performances than the polyethylene/metal couples. Furthermore, the ratio of wear rates for polyethylene cups against alumina and the metallic femoral heads was 0.5, which agreed well with that deduced from clinical studies or laboratory hip simulators. It is obvious that these comparable wear behaviors observed from clinics or laboratory studies also can be found by means of the numerical simulation.

The dry sliding wear behaviour of cast aluminium reinforced with hematite was investigated by means of pin-on-disc wear testing machine. The composite specimens were prepared using liquid metallurgy technique. Wear rates of the composites varying from 0 to 5 % by weight hematite were measured over a load range of 9.81 to 49.05 N at sliding velocities of 1.35,1.8 and 2.25 m / sec. Detailed scanning electron micrography (SEM) was done to verify the effect of addition of hematite on wear mechanism with and without heat treatment. Observations indicate that wear rate of the composites was less than that of the matrix alloy, but increased with the increase in load and the sliding velocity. Heat treatment at 220-degree centigrade upto 5 hours in steps of 2 hours duration improves the wear resistance of the composites.