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This study investigates the development of Ni-Co/SiO 2 nanocomposite coatings on mild steel surface using pulsed-current electrodeposition method. The effects of incorporating SiO 2 nanoparticle and varying its concentration on the coatings' microstructure, microhardness, wear resistance, and frictional properties were assessed using field-emission electron microscopy, X-ray diffraction, Vickers microhardness testing, and dry sliding wear tests. The results indicated that the coatings exhibited two-phases of Ni-Co solid solution (α) with a face-centered cubic (FCC) crystal structure and hexagonal Co, a refined crystallite size of approximately 31 nm for Ni-Co and about 25 nm for Ni-Co/SiO 2 , along with a colony-like morphology that did not show any preferred growth direction. The amount of Ni-Co solid solution increased with the addition of SiO 2 nanoparticles. The composite coatings demonstrated enhanced microhardness of 581 HV, which is 52 % greater than that of the Ni-Co coating, as well as improved wear resistance and a reduced friction coefficient compared to the unreinforced alloy coating. However, higher SiO 2 content adversely impacted the tribological properties due to nanoparticle agglomeration. Analysis of the worn surfaces revealed a transition from abrasive wear to oxidative wear with increasing applied force for the coatings. [ABSTRACT FROM AUTHOR]

This research paper investigates the frictional and thermomechanical properties of a copper (Cu) free non-asbestos organic (NAO) composite for developing brake friction material for automotive/railway applications. Reduced-scale brake composites were manufactured and tested in a pin on disc tribometer. The effect of aluminum (Al) chips on the dry sliding wear behavior of acrylonitrile-butadiene rubber (NBR) modified phenolic resin-based reduced-scale friction composites was investigated. Other common ingredients of friction materials like fiber, filler, and friction modifiers were not included to get the specific effect of Al on the various properties of the composites. Four composites were prepared with varying Al content, for example, 25, 50, 75, and 100 phr (parts per hundred resins). The average COF increases by ∼70% for 75 phr Al loaded composite (optimum composition) compared to the base composite (devoid of Al). However, mechanical properties, such as hardness and flexure strength, decrease with increasing phr of Al, although compressive strength does not change significantly. The optimum composite exhibits the lowest specific wear rate among Al chips loaded composites. The optimum composite also shows nearly three times improvement in thermal conductivity compared to the base composite. The wear behavior of the composites has been analyzed from the scanning electron microscopy (SEM) images. [ABSTRACT FROM AUTHOR]

In the study, the effects of hybrid reinforcement (nano-alumina and MWCNT) and heat treatment on the wear behavior of the Al–4Cu nanocomposites were investigated under dry sliding condition against W–6Co ball by means of a ball-on-disk type tribometer. The load and the sliding speed were kept constant and selected to be 10 N and 0.1 m s−1, respectively, in the course of the wear tests. Meanwhile, the wear tests were completed after a total sliding distance of 1500 m was reached for each case. During these tests, the wear loss of the nanocomposites was measured at every 250 m. The worn surfaces of the nanocomposites were examined with the help of stereo and scanning electron microscopes. The volumetric wear rates, wear coefficients and wear mechanisms were identified for the nanocomposites to clarify the influence of reinforcement content and heat treatment on their wear resistance. The volume loss at the wear distance of 1500 m was obtained as 24.9 and 8.2 mm3 for the annealed and aged Al–4Cu alloy, respectively. On the other hand, it decreased to 4.6 and 3.2 mm3 in the case of the nanocomposites with 15% hybrid reinforcement in the annealed and aged conditions, successively. Moreover, increasing the hybrid reinforcement amount decreased the wear loss of the aged nanocomposites substantially in such a way that it resulted in the mild wear. [ABSTRACT FROM AUTHOR]

Researchers have long been studying the effects of the modification of friction material compositions on their tribological properties. Predictive models have also been developed, but they are of limited use in the design of new compositions. Therefore, this research aims to investigate the tribological behaviour of single ingredients in friction materials to develop a tribological dataset. This dataset could then be used as a foundation for a cellular automaton (CA) predictive model, intended to be a tool for designing friction materials. Tribological samples were almost entirely composed of four distinct friction material ingredients, and one sample composed of their mixture was successfully produced. Pin-on-disc (PoD) tribometer testing and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDXS) analysis were used for the tribological characterization. Each material showed distinct tribological properties and evolution of the contact surface features, and the synergistic effect of their mutual interaction was also demonstrated by their mixture. [ABSTRACT FROM AUTHOR]

The goal of the current study was to develop functionally graded in-situ Al-17Si-Al3Zr/Al2O3 composites by approaching the vertical centrifugal casting method (VCCM). The two different proportion of Zr(CO3)2 powder (10 wt.% and 15 wt%) were added in to molten matrix to form the in-situ reinforced particles Al3Zr/Al2O3. The polyhedral shapes like Al3Zr and fine globular Al2O3 particles were formed into molten Al-17Si aluminum alloys. The accumulation of Al2O3 (ρ≈3.99 g/cm3) and Al3Zr (ρ≈4.11 g/cm3) in the vicinity of the outer zone was caused by centrifugal force. Additionally, particle coalescence and Ostwald ripening processes were found to be responsible for the clustering of eutectic silicon particles. The gradient distribution and morphologies of particles were characterized using SEM and OM microscopy. The constituent phases were analyzed via energy dispersive spectrometry (EDS) and XRD analysis. The hardness value was lower on the inner layers and higher on the outer layer. However, as compared to basic alloys, the hardness value of Al-15%Zr(CO3)2 increased by 64.7%. The dry sliding wear test involved the following variables: sliding velocities (m/s), sliding distances (m), and the normal applied load (N). The peak mass loss showed up with a load of 40N during wear property measurements. [ABSTRACT FROM AUTHOR]

As it is known, Polytetrafluoroethylene (PTFE) is one of the most preferred polymeric materials for tribological applications. This study investigates the performance of PTFE and its composites under different tribological conditions. The effects of short glass fiber (GF), carbon particle (CP) and bronze particle (BP) reinforcement agents and their hybrid filling with molybdenum disulfide (MoS2) on sliding, erosive and abrasive wear were examined. Sliding tests were carried out with a ball‐on‐disc test apparatus, erosive wear tests were carried out with solid particle erosion and abrasive wear tests were carried out with a scratch test. It has been found that reinforcement agents improve sliding and abrasive wear resistance but worsen the erosion resistance. The hardness and contact angle of the samples were associated with their wear performances. Topographic and morphological analyzes of worn surfaces were performed using optical profilometer and scanning electron microscopy (SEM), respectively, and wear mechanisms were discussed. Highlights: Filling materials (glass fiber, carbon particle and bronze particle) increase the adhesion and abrasion resistance of PTFE, while decreasing its erosion resistance.The effect of hybrid addition of MoS2 solid lubricant on wear performances depends on the type of filler.There is a correlation between surface properties (hardness and contact angle) and wear performances.Optical profilometer and scanning electron microscopy were used to examine wear mechanisms. [ABSTRACT FROM AUTHOR]

AbstractThe experimental study assessed the impact of choline chloride cation-based ionic liquid (IL), on the dispersion stability and wear characteristics of copper (II) oxide (CuO) nanoparticles (NPs) in synthetic base oil (PAO 10). CuO NPs, averaging 50 nm in size, underwent surface modification using varying concentrations of the IL (0.25%, 0.5%, 0.75%, and 1% by weight). The formulations were subjected to sliding wear tests to evaluate their wear behavior. Analysis of the worn surfaces utilized scanning electron microscopy, energy-dispersive x-ray spectroscopy, and atomic force microscopy. The results indicated that the combination of 0.75% IL and 1% CuO NPs provided optimal dispersion and exhibited effective surface mending, enhancing wear protection by 21.1% than that of PAO 10. The formulation containing 1% IL and 1% CuO NPs demonstrated the highest load carrying capacity among all tested compositions. In terms of wear behavior, the nanolubricant formulations with 0.75% and 1% IL outperformed the lubricant formulation containing 1 wt% of the commercial antiwear additive Zinc dialkyldithiophosphates (ZDDP). [ABSTRACT FROM AUTHOR]

To improve the tribological properties of polar crane copper alloy bearings to withstand wear under dry sliding wear and grease lubrication at low temperatures, three kinds of coating materials modified by incorporating WS2 and SiC into polyamide‐imide/polyimide‐phenolic epoxy resin were designed. These composite coatings were sprayed on the surfaces of CuPb22.5Sn2.5 copper alloys by liquid spraying technique. Firstly, the tribological experiments were performed with three different coatings. Then, nanoindentation testing and wear morphology analysis were conducted. The results show that the hardness of the composite coatings decreases with the increase of WS2. As the content of WS2 increases, the coefficients of friction (CoFs) of coatings decreases under dry sliding wear. The S2 coating filled with 7.5 wt% WS2 exhibits the lowest wear rate and the best wear resistance under low temperature and dry sliding wear. The coatings form a lubricating film on the worn surface under dry sliding wear at −70°C, improving the wear resistance of the coatings. The primary wear mechanisms are adhesive wear and fatigue wear. The wear rates of the coatings increase with the increasing content of WS2 under low‐temperature grease lubrication. The S1 coating filled with 5.0 wt% WS2 exhibits the lowest wear. The S1 coating demonstrates a CoF of 0.07 and a wear rate of 6.5 × 10−6 mm3N−1 m−1 at 0°C, showing excellent friction‐reducing and wear‐resistant properties. The primary wear mechanism is adhesive wear. The wear mechanisms of polymer coatings are closely related to temperature. The dominant wear mechanisms transfer from abrasive wear to adhesive wear and fatigue wear under dry sliding wear and decreasing temperature. The wear mechanisms transfer from predominantly adhesive and abrasive wear to adhesive wear, fatigue wear, and abrasive wear under grease lubrication. The hardness of the coatings and the behavior of the polymer at various low temperatures are the primary factors that affect the differing wear mechanisms. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of nitrogen content on the tribological behavior of 316L (N) stainless steel at three different nitrogen levels: 0.07, 0.11 and 0.22 wt. percent. AISI 316L (N), an austenitic stainless steel, is the primary structural material used in sodium-cooled prototype fast breeder reactors (PFBR). Wear tests were conducted using a pin-on-disc tribometer, with a sliding velocity of 0.8 m/s and a normal load of 40 N, over a sliding distance of 1000 m. The experiments were carried out against an Inconel 718 counter face material at four different temperatures: room temperature, 200 °C, 400 °C and 550 °C. The dry sliding wear tests were performed in a vacuum of 10–6 torr to simulate wear in liquid sodium. The investigation covered the properties of the three grades of stainless steel, including microstructure, hardness, X-ray diffraction (XRD), specific wear rate, wear resistance and wear coefficient. This study also compared three different wear models a weight loss model, an ASTM model, and geometric models highlighting the reported anomalies. Scanning electron microscope (SEM) photographs of the worn surfaces were used to assess the severity and mode of wear. It was discovered that wear resistance decreases as temperature increases due to the material's thermal softening, and that the stainless steel with 0.07 wt% nitrogen exhibited the best wear resistance among the tested compositions. [ABSTRACT FROM AUTHOR]

The friction and wear of B 4 C ceramics with different contents of Al 2 O 3 /Y 2 O 3 sintering additives were studied under dry sliding. With the increase of Al 2 O 3 /Y 2 O 3 content, the friction coefficient of B 4 C ceramics decreases first and then increases, and the wear rate of B 4 C ceramics decreases gradually. The friction coefficient of B 4 C ceramics is related to the amount of wear debris generated on the sliding interface, which is determined by the competition between the number of pores that can trap the wear debris and the degree of grain pullout and grain fracture. When the content of Al 2 O 3 /Y 2 O 3 is 5 wt%, the amount of wear debris on the sliding interface is the least, leading to the lowest friction coefficient. The wear rates of B 4 C ceramics are controlled by the competition of the beneficial effect of improved relative density and mechanical properties and the adverse effect of weak bonding between B 4 C grains due to the formation of intergranular phase. The gradually decreased wear rate of B 4 C ceramics with the increased content of Al 2 O 3 /Y 2 O 3 is attributed to the improved relative density and mechanical properties. [ABSTRACT FROM AUTHOR]

This investigation employs the salt bath nitriding to extend the service life and improve the surface characteristics of AISI 52100, commonly employed in bearing applications. A wear test was conducted using a pin-on-disc device according to the ASTM G-99 standard, and the findings show a 30% reduction in wear loss. Sliding wear experiments were conducted at 1.5 m/s with a 5 N force at room temperature on uncoated and nitrided pins which was obtained as optimum value from RSM. The three variables and five levels of central composite design (CCD) were utilized to reduce the number of trials and the model relations were examined through ANOVA. Surface hardness, friction coefficient, wear coefficient, and loss in wear are measured over pins without coating and nitride pins. Investigations were done into how 5W30 oil affected passive and drip lubrication. Nitride substrates had a hardness of 590 HV. Also, nitriding has a favorable effect on the friction coefficient, lowering it by up to 23%. The 5W30 lubricant will further decrease the friction coefficient. The lowest friction coefficient was seen with the addition of 14% drip oil lubrication. Significantly less wear loss in the pin was caused by a combination of high hardness and low friction coefficient. [ABSTRACT FROM AUTHOR]

The present study adopts a multi-facet approach to design bio inspired concentrated alloys for potential application as articulating surfaces in joint replacements. A series of equiatomic, Nb rich and Ti rich TiMoNbZr based medium entropy alloys (MEAs) were processed via arc melting and their mechanical, in-vitro corrosion, wear, and in vitro and in vivo biocompatibility were investigated. Equiatomic MEA had primarily bcc with minor hcp phases where the single bcc was achieved with the addition of Nb. The single bcc Nb rich alloy resulted in 13 % elongation, much higher than equiatomic or Ti rich alloy. All the MEAs showed comparatively higher yield strength due to the climb of edge dislocations which is the main rate limiting mechanism at 300 K, as evident molecular dynamics (MD) simulation. The locally fluctuating energy landscape promotes kinks on edge dislocation, and at local minima nanoscale segments gets pinned. Upon yielding the entangled kink leaves a trail of vacancies/interstitials and escapes via climb motion to render high yield strength. The higher corrosion and pitting resistance of Nb enriched alloys can be attributed to the stable ZrO 2 , Nb 2 O 5 , TiO 2 , and MoO 3 oxides, high polarization resistance (106–105 Ωcm−2), and low defect densities (1016–1018). In vitro cell-materials interaction using MC3T3-E1 showed bioinert but cytocompatible nature of the MEAs. The wear rate of the MEAs was in the range of 7–9 × 10−5 mm3N−1m−1. The wear debris did not show any tissue necrosis when implanted in rabbit femur rather new bone regeneration can be seen around the particles. In the present work, a noble Nb enriched MEAs with superior mechanical, in vitro wear, corrosion and cytocompatibility properties was designed for articulating surfaces in joint replacement. • Single bcc in Nb enriched MEAs resulted in 13 % elongation with high hardness and yield strength. • Climb of entangled edge segment is the rate limiting mechanism in controlling high yield strength of MEAs at 300 K. • High polarization resistance (106–105 Ωcm−2), and low defect densities (1016–1018) attributes to ZrO 2 , Nb 2 O 5 , TiO 2 , and MoO 3 oxides enriched passive film. • Wet sliding wear rate ranged in order 7–9 × 10−5 mm3N−1m−1. In-situ generated wear debris when implanted in rabbit femur did not show any tissue necrosis rather new bone regeneration was observed around debris. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigates and establishes the effect of welding process parameters on the tribological performance of the fabricated weld using the gas tungsten arc welding (GTAW) process. Both ER 2594 and ER 70S-2 were used as filler metals to fabricate a dissimilar GTA weld between sDSS 2507 and N50 steels. sDSS 2507/N50 DWJs have substantial importance to the subsea oil-gas drilling industries, especially in tubing and coupler assembly. The thermodynamic study predicts microstructure evolution during weld fusion zone cooling. Dry-sliding tribology behaviors were investigated using a pin-on-disc dry-sliding wear tester with a constant load of 30 N, sliding speeds from 1.111 to 6.666 m/s, and distances from 500 to 3000 m. Scanning electron microscopy examined the worn surface's wear mechanism and progression. ER70S2-LHI specimen had the lowest volume loss (12.83 mm3), and the N50 BM exhibited the greatest (112.65 mm3). Due to its martensitic structure, ER70S2-LHI has the lowest wear rate (4.28 × 10–3 mm3/m), while N50BM demonstrates the highest wear rate (37.5 × 10–3 mm3/m). For both LHI and HHI weld conditions, ER70S2 filler welds outperform ER2594 filler welds by 85 and 60%, respectively, in volume loss and by 81 and 48%, respectively, in wear rate. N50 BM had poorest wear progression and the ER70S2-LHI weld zone the most. Sliding wear on pins from base metal and filler weld zones exhibits mixed-mode abrasive, adhesive, and fatigue wear, producing material removal as spalling and flaking. [ABSTRACT FROM AUTHOR]

Because of its improved formability, lower production costs, and mechanical properties, aluminum metal matrix composite is the highly intriguing engineering material. It can meet the needs of modern engineering applications used in the automotive, military, aerospace, and marine industries. Hybridization of reinforcement is adopted to develop tailor‐made properties of composites for specific application. In this study, Al‐B4C‐Gr hybrid composites were produced with varying graphene content (0.25, 0.50, 0.75, and 1 wt.%) and keeping boron carbide (10 wt.%) as constant, the effect of graphene proportion on the mechanical properties of produced composites was evaluated. It has been observed that increasing the Gr reinforcement particles in the synthesized composites improves the mechanical characteristics of the composites, such as raising the tensile strength to 215 Mpa and the hardness to 110 HV due to the presence and proper distribution of reinforcement in the matrix. When compared to the base alloy, the tensile strength and hardness of Al10B4C0.75Gr composites rose by 27.174% and 67.290%, respectively. The dry sliding wear behavior of Al‐10 wt.% B4C‐wt.%Gr hybrid composites confirms that graphene and B4C particles in the matrix increase the wear resistance of the produced MMCs. The each parameter such as sliding distance, sliding velocity and load has its influence toward the better wear resistance of the developed composites and were discussed. [ABSTRACT FROM AUTHOR]

This work uses a novel stir-ultrasonic-squeeze casting technique to fabricate hybrid nanocomposites based on aluminium alloy 6061 (AA6061). Owing to its excellent strength, ability to withstand corrosion, and formability as a matrix material, AA6061 was chosen. The process involves adding boron carbide (B4C) & graphite and (Gr) nanoparticles (np) to the aluminium melt, followed by mechanical stirring, ultrasonic agitation, and squeeze casting to produce the sound casting. The weight percentages of (B4C and Gr) np were taken at a constant 2wt%. The mechanical and tribological properties of these hybrid metal matrix nanocomposites (HMMNCs) are examined in this study. A Brinell hardness number and ultimate tensile strength (UTS) in MPa examined are 66.9 and 197.01 with a 27.02% and 4.06% increment for (2wt%B4C+2wt%Gr). A pin-on-disk (POD) tribometer was used to analyze the dry sliding wear of the composite. Significantly, compared to AA6061 (as cast), the wear characteristics show a lower average coefficient of friction and wear rate for 2wt% HMMNCs. For all loads and sliding velocities, a better increase is thus seen, highlighting the better mechanical and tribological performance of 2wt% B4C with 2wt% Gr. [ABSTRACT FROM AUTHOR]

Transparent yttrium aluminum garnet (YAG) exhibits high hardness and abrasive resistance, making it a promising candidate for applications involving material contact, such as protective optical elements, windows, domes, and armors. When transparent YAG is employed in such applications, it may be susceptible to degradation due to friction, chemical exposure, or thermal stress. Despite its potential, there is limited research on the tribological behavior of transparent YAG. In the present study, transparent YAG ceramics were fabricated by reaction sintering of high‐purity Al2O3 and Y2O3 powders. The transparent YAG specimens had an average grain size of 20 ± 6 µm and hardness of 1068.98 ± 115.15 HV, and fracture toughness of 1.27 ± .06 MPa.m0.5. The effect of load variation from 5 to 15 N on the tribological behavior of transparent YAG was investigated when slid against chrome steel (100Cr6) balls with a hardness of 815 ± 75 HV. The low coefficient of friction (COF) and wear rate were observed due to the wedge formation (fish‐scale‐like pattern) at the surface when the load was increased from 5 to 10 N. Moreover, tribochemical layer formation, fracture, and material transfer were observed when the load was increased from 10 to 15 N, leading to high COF and increased wear rate. [ABSTRACT FROM AUTHOR]

The material for a cutting tool needs to be carefully selected to withstand high temperatures during cutting and have good wear performance. The use of cutting tools made from cemented carbide material was studied due to its potential in terms of mechanical properties that are ideal at high temperatures up to 1000 °C and being cheaper than other materials. This investigation of the dry wear of this cutting material focused on temperatures of 25 °C, 200 °C, and 300 °C, with loads of 50 N, 100 N, and 150 N. The weight loss, friction coefficient, and change of the pin microstructure were determined. It was found that the higher the temperature and load applied to the cemented carbide pin, the more the microstructure changed, and the percentage of weight loss increased up to 0.55%. The wear rate on the cemented carbide pins was higher when applied to a stainless steel disc compared to a mild steel disc. The simulation revealed that the von Mises stress on the stainless steel disc was 51.759 Pa, while that on the mild-steel disc was 60.379 Pa. This indicates that both materials did not fail because the von Mises stress was lower than the disc yield stress. [ABSTRACT FROM AUTHOR]

Metal matrix composites have captured considerable interest in tribological applications, largely owing to their remarkable characteristics, which include a high strength-to-weight ratio and a low wear rate. This investigation delves into the exploration of hybrid metal matrix composites, where cobalt and chromium play the role of reinforcing agents within a bronze foundation. These composites were manufactured through a powder metallurgy process, utilizing cobalt and chromium metal powders with a particle size of 40 μm. Various weight percentage ratios (2.5%, 5.0%, and 7.5%) were utilized to create these composite specimens. To assess their tribological performance, the composite samples were subjected to a sliding wear test using a pin on disk machine, following the ASTM G99 standards. The wear characteristics of these composites were analyzed using the Taguchi method, considering parameters such as the applied load, speed, reinforcement percentage, and sliding distance. In addition, we conducted an analysis of variance on the collected data. To analyze the wear behavior of these hybrid metal matrix composites based on bronze, we utilized both multiple linear regression analysis and a signal-to-noise ratio assessment. The results indicate that the inclusion of cobalt and chromium metal powders as reinforcement materials enhances the tribological properties of the bronze matrix material. [ABSTRACT FROM AUTHOR]

The running-in period during dry sliding wear might determine the evolution to steady-state wear behaviour. To this end, the running-in period during sliding wear of austenitic stainless steel, AISI 316L stainless steel, and Hadfield steel were studied through the testing pin (flat-ended)-on-disk configuration. The effects of the normal load, sliding speed, and alloy type were assessed, and the specific wear rate and strain hardening characteristics were determined. The wear rate was correlated with wear mechanism, friction coefficient, hardening, and roughness to characterize the changes occurring during the running-in period. These changes could influence the responses of these materials to wear during the steady-state period. The stabilization of the specific wear rate and hardness was noted to align with the end of the running-in period. [ABSTRACT FROM AUTHOR]

The service performance of polycrystalline cubic boron nitride (PcBN) tools undergoes significant changes due to the deep space environment to the structure and wear behaviors of PcBN. In this paper, the effect of cryogenic treatment (CT) was studied to investigate the physical and tribological behaviors of PcBN. The hardness and wear resistance of PcBN are improved but wear forms are not affected, which are abrasive wear. The shedding of cBN played the role of micro-cutting edges, carving furrows on surfaces. As the CT duration increases, the wear rate of PcBN decreases from 2.56 × 10−8 mm3/N mm to 1.61 × 10−8 mm3/N mm for sliding against Si 3 N 4. When PcBN slid Al 2 O 3 , the lowest wear rate is 1 × 10−8 mm3/N mm which the decline reached 34 %. Due to discrepancies in physical and mechanical properties, Si 3 N 4 and YG8 balls exhibit abrasive and adhesive wear, and Al 2 O 3 shows fatigue wear. Until the fatigue failure appeared, Al 2 O 3 exhibited the lowest wear rate of 2.30 × 10−9 mm3/N mm. Among three materials, the wear rate of Si 3 N 4 was the highest. By calculating the wear rate ratio of the materials, it was concluded that the optimal removal efficiency was achieved for Si 3 N 4 and YG8 when CT duration is 24 and 48 h, respectively. [ABSTRACT FROM AUTHOR]

(NiCrW) 1-x (Al 2 O 3) x composites with different nano-Al 2 O 3 ratios (x = 0, 1, 2.5, 5 wt %) were prepared using powder metallurgy techniques. The influence of the Al 2 O 3 content on the microstructure, phase composition, high-temperature mechanical properties, and wide-temperature-range friction and wear performance of the composites was investigated. The corresponding high-temperature strengthening and wear-resistance mechanisms were also investigated. The results indicated that as the alumina content increased, the tensile and compressive strengths of the composites decreased at room temperature (RT). However, at high temperatures (800 °C), the opposite trend was observed. Notably, the composite with 5 wt % Al2O3 exhibits the highest tensile strength (189.20 MPa) and compressive strength (446.61 MPa) at 800 °C. The addition of alumina had a relatively minor impact on the friction coefficient of the composites but significantly affected the wear rate. Specifically, the composite with 5 wt % Al 2 O 3 demonstrates optimal friction and wear performance at high temperatures. This enhancement was primarily attributed to the reinforcement of the mechanical properties of the matrix material owing to the addition of alumina. Additionally, the formation of a friction glaze layer rich in Cr 2 O 3 and NiO oxides on the worn surface contributed to improved wear resistance. This study is important for understanding the performance and applications of metallic materials. [ABSTRACT FROM AUTHOR]

This study concentrates on NiCrAlY-based coating with nano-boron carbide and cenosphere particles. The composition of NiCrAlY, B4C and cenosphere are maintained the same for all the samples. The plasma spray technique is used for coating. The erosive wear is carried out for different impingement angles of 30°, 60°, 75° and 90° at 900°C. The morphology of coating before and after erosive wears is studied using scanning electron microscopic analysis. Further, the study is carried out on surface roughness, scratch resistance and coefficient of friction of the eroded surface of the samples. The significant erosive wear resistance is reported for an impact angle of 60° followed by 30°. The surface roughness results reveal the formation of deep craters and the ploughing effect of material on the coatings. The scratch test and COF show the presence of coating and the brittle nature of the failure of the coating. [ABSTRACT FROM AUTHOR]

The wear and friction characteristics of the CuSn10P1 copper alloy are influenced by various factors, including the sliding velocity and applied force. An investigation has been conducted to examine the influence of various loads and sliding velocities on the wear characteristics of the thixoextruded copper alloy. The annealed alloy exhibits a homogeneous distribution of the solid phase, and a liquid island presents in the solid phase. The major phases consist of α-Cu, Cu41Sn11, and a few Cu3P phases. The average coefficient of friction (COF) is between 0.6 and 1.0. SEM-EDS and three-dimensional topography instruments were used to analyze the surface topography and wear rate of reciprocating wear. When the sliding velocity was 5 mm/s, the wear rate increases from 0.07 mm3/Nm to 0.226 mm3/Nm as the load increases from 3 N to 9 N, in accordance with Archard's dry wear law. The worn surface exhibited groove, granular, and layered debris, and the predominant characteristics of the wear were abrasive wear and delamination wear. As the load increased, there was a transition from abrasive wear to delamination wear. [ABSTRACT FROM AUTHOR]

The present study uses the compo-casting technique to fabricate cenosphere-reinforced Al5052 alloy. The wear tests were performed utilizing a pin-on-disk apparatus to examine the impact of load, sliding speed, and reinforcement wt.% on the wear rate. Employing response surface methodology (RSM), this research delves into the influences of load, sliding speed, and cenosphere content on the responses. As per the ANOVA analysis, load exhibited the most substantial effect. The ramp plots unveiled the optimal combination for minimizing wear rate identified as 200 rpm sliding speed, 10 N load, and 0 wt.% cenosphere reinforcement. The desirability plots reveal that the prediction value for wear rate is 0.7695 mm3/Nm at a desirability of 96.8%. Incorporating cenosphere particles as reinforcement increased the wear resistance of the aluminum metal matrix composites (AMMCs). [ABSTRACT FROM AUTHOR]

Polymeric materials are widely used in aerospace, biomedical, marine, and agricultural applications due to their viscoelasticity and corrosion resistance. Polymeric materials fail due to wear during their service life, so studying their wear behavior is essential to control and predict their service life. This paper summarizes the progress of water lubrication research as well as experimental studies on the wear of polymeric materials under aqueous conditions. The effects of lubrication conditions, material formulation ratios, load, sliding speed, impact angle, abrasive particles, and temperature factors on the wear behavior of commonly used polymeric materials ideal for water lubrication (NBR, SBR, NR, EP, polyethylene, and their composites, etc.) are summarized in terms of the three most frequently occurring forms of wear, namely, two-body wet sliding wear, two-body erosive wear, and three-body wet abrasive particle wear. The results show that the mechanical properties, such as hardness, can be effectively changed by altering the formulation ratios of the materials, and the hardness and hydrophilicity of the formulations can further affect the wear and lubrication. In general, the coefficient of friction and the wear rate decrease with the increase in hardness, and the increase in temperature leads to the localized lubrication failure and the aging of the materials, which in turn leads to the intensification of wear. Among the working condition factors, load and sliding speeds are the most important factors affecting the wear, and the wear rate increases with the increase in the load and sliding speed; in contrast, the three-body wet abrasive wear is more obviously affected by the load. In the study of the impact angle effect, the overall trend of the erosion wear rate with the increase in the angle shows the first rise and then fall, the maximum value is mostly concentrated in the 45–60° between. Usually, the increase in the abrasive particle size can make the wear rate increase. Overall, the three-body wet abrasive wear of the rubber material wear rate shows first an increase and then a decrease. The research in this paper provides theoretical support and reference ideas for the tribological study of polymer materials in the water environment and puts forward the outlook for future water lubrication and material improvement of the research directions and applications. [ABSTRACT FROM AUTHOR]

Aluminum metal matrix composite (AMMC) is employed in all engineering applications, most notably as a substitute for conventional metals in the fields of defense, automotive, and aerospace. AMMC should have a wide variety of structural, mechanical, thermal, wear, and corrosion qualities that may require mutually exclusive features at an optimal level to achieve this. The current research focuses on the stir casting process for producing SiC and cenosphere reinforced Al7075 alloys. The response surface method's (RSM) face‐centered central composite design (CCD) was used to design the number of experimental trials, and a response surface technique was enforced to forecast the optimum combination of processing variables in the wear process. The SiC reinforcement improved the wear resistance of Al7075‐SiC‐cenosphere composites substantially. Overall, the experiments show that Al7075‐6 wt% SiC‐5 wt% cenosphere has excellent tribological properties. The hybrid Al7075/SiC/Cenosphere composites were shown to be effective, fit, and suitable in the ideal wear process parameters (load of 10 N, sliding distance of 1000 m, and sliding velocity of 1.5 m/s) for lowering wear rate (0.38035 × 10−3 mm3/m) at 6wt% SiC reinforced composite. This suggests that the combination of SiC and cenosphere improves the wear resistance of AMMC. [ABSTRACT FROM AUTHOR]

Dry sliding wear tests on Cu-Al-Mn Shape Memory Alloys (SMAs) were performed in this study. The alloy was synthesised with the amount of manganese content varied as 5, 7, and 9 wt.% and the amount of aluminium was kept constant at 10.5 wt.% with the remaining copper. Dry sliding wear tests were carried out at different conditions of sliding speeds, sliding distances, and various load conditions. Experiments were carried out using Taguchi's technique to obtain an experimental design. The data were analysed using an L27 orthogonal array. The wear rate (WR) and coefficient of friction (COF) were evaluated using the 'smaller is better' method approach. The main parameters affecting WR and COF were determined using ANOVA. The effects of applied load, sliding speed, sliding distance, and material on WR and COF are determined. The optimum combinations of parameters were set to achieve the lowest wear rate and highest COF. Finally, confirmation tests were conducted to ensure that the experimental results were accurate. After the wear test, the sample texture was observed and analysed using a Scanning Electron Microscope (SEM). [ABSTRACT FROM AUTHOR]

Wear is a major issue in industry, particularly with metal components. Therefore, it is crucial to investigate methods that offer increased resistance to this phenomenon. In this research, three coating systems (pure WC-CoCr and WC-CoCr/NiCrFeSiBC+Mo, 88:12 and 83:17 wt.%) were thermally sprayed on an AISI 1018 steel substrate through the High-Velocity Oxygen Fuel (HVOF) process. The coatings were characterized using a field emission scanning electron microscope (FESEM) equipped with the energy dispersive spectroscope (EDS) and X-ray diffractometry (XRD). An analysis of the wear rate for ball-on-flat linear reciprocating sliding tribological tests for the coatings was also carried out. The coating microstructure presents well-dispersed NiCrFeSiBC splats. The WC-CoCr/NiCrFeSiBC+Mo, 88:12, system has the highest wear resistance, decreasing by 30.2% at high loads compared to commercial WC-CoCr CERMETs, and also exhibits the highest fracture toughness. Analysis of wear tracks shows that the material removal at all charges occurred mainly by an abrasive wear mechanism. [ABSTRACT FROM AUTHOR]

The object of this work is the effect of a laser beam surface treatment on the micro-mechanical and tribological properties of biomedical Co-28Cr-6Mo alloy manufactured by different methods (casting-forging or Laser Powder Bed Fusion (LPBF)). The wrought and LPBF alloys were superficially melted by the laser beam of 400 W power (fiber laser «TruFiber 400» (TRUMPF) of 1064 nm wavelength) under a scanning velocity of 5 mm·s-1. The research was fulfilled using an optical (GX71 OLYMPUS) and electron scanning microscopy (JSM-7000F JEOL), X-ray diffraction (X'Pert PRO, PANalytical, Cu-Kα radiation), nanoindentation (“G200 Nano Indenter”, Agilent Technologies) and tribological testing (a “Ball (Al2O3)-on-Plate” sliding in a simulated body fluid). It was found that laser treatment resulted in a modified (remelted) layer with a depth of 500-550 μm having mainly the εCo phase (HCP) structure formed by dispersed dendrites. The dendrite cross-section size varied from 5-12 μm (in the primary arms) to 1.5-6.0 μm in the secondary arms; these values are much lower than the average grain size in the wrought unmodified alloy (44 µm). Laser treatment increased the hardness and yield strength of the wrought alloy by 23 % (to 5.21 GPa), and decreased the volume wear by 25 %. In contrast, laser surface melting hardly changed the micromechanical and tribological properties of the LPBF alloy since its structure was not refined relatively the as-printed (unmodified) state. However, the melting-induced densification (porosity elimination) of the modified layer was observed in the LPBF alloy thus indicating the positive effect of laser modification on the structure of the LPBD-manufactured components. [ABSTRACT FROM AUTHOR]

The present work investigates the dry sliding wear and friction behaviour of an alloy steel developed through powder metallurgy. Prealloyed Atomet 4601 powder was thoroughly mixed with elemental powders of 0.35 C, 0.25 Mn, 0.1 Si and 0.9 Cr (in wt. %) to create this alloy steel, whose composition closely matches EN24 (AISI 4340) wrought steel. The dry sliding friction and wear test experiments were performed in a pin-on-disc tribometer. For the various cases considered in friction and wear tests, the wear rate is lowest (0.32 × 10–3 mm3/m) at 15 N and 1.77 m/s and highest (1.02 × 10–3 mm3/m) under severe conditions of 32.5 N and 2.83 m/s. The coefficient of friction is highest (0.673) at 15 N and 0.71 m/s and lowest (0.1311) at 32.5 N and 2.83 m/s. Subsequently, regression models are developed based on experimental results and the interaction effect of load and speed on the response parameters are plotted using MATLAB. An R2 value of 0.98 indicates a strong correlation between the response and the input variables. X-ray diffraction (XRD) and optical and scanning electron microscope (SEM) analyses of the most worn specimens revealed carbides and oxides in the ferrite grain matrix, with adhesive, abrasive and oxidative wear being the primary mechanisms observed

The objective of the present investigation is to assess the impact of AlMg1SiCu alloys with soft and hard microparticle reinforcements affects the dry sliding wear behavior of metallic composites at elevated temperatures. Traditional fabrication techniques of melt-stir casting were employed for processing the ex-situ-synthesized hybrid composites. Molybdenum disulfide (MoS2) and Titanium carbide (TiC) microparticles were added in different quantities varying from 1 to 3% MoS2 to a constant 8% TiC. Materials underwent testing across a range of temperatures to simulate wear conditions prevalent at elevated temperatures: 453 K, 473 K, 493 K, and 513 K. Wear tests at elevated temperatures were systematically conducted under consistent parameters, encompassing a sustained load 24.5 N, sliding speed 3.14 m/s and sliding distance of 2000 m for each trial. The comparative analysis with the AlMg1SiCu matrix material, Observations revealed an enhancement of wear resistance at the temperature range of 513 K for the chosen hybrid composites. A comprehensive discussion was undertaken regarding high temperature dry sliding characteristics of the matrix material and hybrid composites. The study of the worn surfaces revealed the high-temperature wear behaviour of hybrid composites encompassed adhesive, delamination, and oxidation wear processes. [ABSTRACT FROM AUTHOR]

The investigation describes the processing and analysis of laser welded Hastelloy-X (HX) alloy joints through this paper. HX alloys are employed in aerospace and nuclear industries, especially for high-temperature applications. In this research, a series of laser beam welding (LBW) experiments denoted as E1 to E9 were conducted on the HX base metal (BM), adhering to the L9-orthogonal array (L9-OA) design matrix. CO2 laser technology was employed to fabricate HX butt joints. The laser power, focal length and welding speed were the variables. Then, the character of each joint was analyzed by sophisticated testing methods as per ASTM standards. The results showed that the character of each sample was varied depending on the selection of parameters. The E5 sample had a maximum tensile strength (TS) and ductility with 93 % joint efficiency. The grain elongation and refinement in the weld zone (WZ) were confirmed through microstructures and electron back scattered diffraction (EBSD) studies. The corrosion character of each joint (E1 to E9) was analyzed using the potentiostatic polarization method. The E1 sample had the highest corrosion resistance. The corrosion rate was in the range of 7.4E−03 to 8.6E−05 mm/yr. The dry sliding wear test (A1 to A9) was carried out as per L9-OA on the E1 sample, since this weld parameter had good corrosion resistance, by varying applied load, sliding distances and sliding velocities. Wear test results showed an increase in wear rate with the increase in load and sliding distance. A wear map was also drawn using the results to find out the association between wear rates and wear parameters. Weld speed had influenced the strength of the joint and laser power had shown an impact on the corrosion and wear of the HX alloy joints. The weld zone, corroded sample and the worn-out surfaces of weld joints were further analyzed using an optical microscope (OM) and Field Emission Scanning Electron Microscopy (FESEM). [ABSTRACT FROM AUTHOR]

This reports the tribological behavior of sintered aluminum composite with bio-oil as lubricant. The composite is fabricated by powder metallurgy route, and the aluminum is reinforced with the particles V2O5 and B4C. The bio-lubricant oil is Pongamia, Jatropha, and blended Pongamia with Jatropha of equal volume. The wear test was carried out at the sliding speed of 3 m/s and load ranging up to 180 N, and the wear behavior of Al–xV2O5–2B4C composite. Then the composite's friction coefficient and weight loss were tested on a pin-on-disc tribometer. Further, pinworn surfaces were analyzed by Scanning Electron Microscope. The mix of Pongamia with Jatropha of equal volume resulted in a good change in specific wear rate and coefficient of friction of composites. [ABSTRACT FROM AUTHOR]

Aluminium-carbon nanotube (Al-CNT) composites have proven to offer a lot of potential for applications involving friction and wear. This study investigated the wear behaviour of Al-CNT composites with uniformly dispersed CNTs without structural damage at concentrations of 0.5 wt%. The wear behaviour of these composites has been compared with that of pure aluminium, which was fabricated using the identical wet shake mixing, compaction, and extrusion procedure. The study aimed to determine how CNT concentration and applied stress influence the wear behaviour of composite materials. Scanning electron microscope (SEM) was used by the researchers to examine the surface features of the worn samples. The study showed a significant increase in hardness and wear resistance with adding CNT. Compared to pure aluminium, the composite containing 0.5 wt. % CNTs demonstrated a 25% reduction in wear rate, and the average value of the coefficient of friction (µ) also decreased. The wear rate and coefficient of friction increased when samples containing 0.5 wt. % CNTs were subjected to various loading scenarios. The major contribution of CNTs to improving wear characteristics was discovered through SEM investigation of these worn surfaces. Using the ANSYS Workbench, a built finite element model was used to perform contact analysis on the disc and pin. Analytical results and experimental data were contrasted, and the ANSYS data was utilised to assess the process parameters. The comparison confirmed the analysis accuracy and dependability, which showed a consistent agreement between the analytical findings and the experimental results. [ABSTRACT FROM AUTHOR]

The growing challenges of reducing exhaust emissions and improved fuel economy has triggered automotive engineers to design and manufacture engine parts with superior mechanical properties and dimensional accuracies. Valve guides are cylindrical structures supporting inlet valve and exhaust valve stems during operation. Conventionally made of grey cast iron material, valve guide suffers from severe wear losses leading to loss of fuel and increased emissions due to improper valve stem seating. Here, the synthesis of a novel ferrous powder metallurgy composite is presented and wear characteristics have been studied at varying loads of 30 N, 40 N and 50 N and varying sliding speeds of 0.5 m/s, 1 m/s and 2 m/s under lubricated conditions. The samples have undergone nitriding heat treatment at 1150 °C to improve surface hardness to 700 Hv. The samples have shown negative wear rates due to high hardness and capillary action of lubricating oil and exhibited stable friction coefficient values. This has been attributed to the formation of hard phases Fe2N, Fe3N, and Fe4N and Fe(Mn)3C and twinning-induced plastic compounds like (Fe24Mn) 0.08 as evident from XRD analysis. The morphological analysis of worn out samples was done with SEM Coupled with EDS and it showed micro-cutting, Ploughing, and delamination as main wear phenomenon.

Highlights This study evaluates the sliding wear behavior of hybrid composites made of epoxy reinforced with alternating layers of flax fiber mats and steel wire mesh. The aim is to enhance the wear resistance of flax fiber‐epoxy composites by incorporating steel wire mesh. Specifically, three composite types are produced by varying their stacking sequences using the simple hand layup technique. Dry sliding wear tests are performed on a pin‐on‐disc test rig under different conditions according to ASTM G99 standard. Taguchi analysis is performed using an L25 orthogonal array and it reveals that sliding velocity is the most critical factor, followed by normal load, in affecting the wear rate of the steel‐flax‐epoxy hybrid composite. Subsequently, a steady‐state wear analysis shows that sliding velocity and normal load increase the specific wear rate (SWR), while steel reinforcement decreases it. ANOVA results indicate that sliding velocity significantly impacts wear rates to the extent of 69.47% for flax‐epoxy composite and more than 70% for flax‐steel‐epoxy composites. Additionally, electron microscopy is used to study the worn surfaces of the composites to determine the wear mechanisms. Successful fabrication of flax‐steel wire mesh reinforced hybrid composites. Wear behavior of multi‐layer composites with different stacking sequence. Use of statistical technique for the prediction of wear rate. Wear mechanisms are identified using electron microscopy. [ABSTRACT FROM AUTHOR]

Aluminium alloys are preferred in various fields, especially in the aviation and automotive sectors, due to their lightweight and durable nature. However, their usage is limited due to weak tribological properties such as low hardness and high adhesion tendency against steel. In order to overcome this deficiency, this study aimed to develop AA7075 matrix composites reinforced with BN and MXene. The productions were conducted by powder metallurgy method with these reinforcements in different ratios, both together and separately. The produced composites were characterized primarily by XRD and SEM analyses, followed by measurement of density and porosity values. Wear tests were conducted using the reciprocating ball-on-flat method, at a frequency of 3 Hz, a sliding distance of 100 m, and a stroke distance of 5 mm, with Inox steel ball. The highest improvement in wear rate was realized under 5 N load at 5 wt.% reinforcement ratios of 48% and 42% for BN and MXene, respectively. When 2 wt% BN and MXene reinforcements were applied together, the improvement rate remained around 34%. It can be said that BN and MXene show promising results by providing significant improvements compared to their counterparts in the literature, with MXene especially warranting further investigation. [ABSTRACT FROM AUTHOR]

In this paper, the morphological, micromechanical and tribological characteristics of the Ti-6Al-4V ELI alloy after thermal oxidation (TO) were identified. TO was carried out at temperatures of 848 K, 898 K and 948 K over a period of 50 h. Microscopic examination revealed that an increase in temperature resulted in an improved uniformity of coverage and an increased oxide grain size. Micromechanical tests showed that TO of the Ti-6Al-4V ELI alloy led to an increase in hardness and deformation resistance. Following oxidation, a decrease (by approximately 10–22%) was observed in the total mechanical work of indentation, Wtotal, compared to the as-received material. The formation of protective oxide films on the Ti-6Al-4V ELI alloy also led to the improvement of tribological characteristics, both when tested under dry friction conditions and in Ringer's solution. The sliding wear resistance increased with an increase in the oxidation temperature. However, a greater degree of wear reduction (by approximately 30–50%) was found for the lubricated contact in comparison with the dry friction tests. Surface roughness also increased with the increase in temperature. [ABSTRACT FROM AUTHOR]

The presented study investigates the effects of weight percentages of boron carbide reinforcement on the wear properties of aluminum alloy composites. Composites were fabricated via ball milling and the hot extrusion process. During the fabrication of composites, B4C content was varied (0, 5, and 10 wt.%), as well as milling time (0, 10, and 20 h). Microstructural observations with SEM microscopy showed that with an increase in milling time, the distribution of B4C particles is more homogeneous without agglomerates, and that an increase in wt.% of B4C results in a more uniform distribution with distinct grain boundaries. Taguchi and ANOVA analyses are applied in order to investigate how parameters like particle content of B4C, normal load, and milling time affect the wear properties of AA2024-based composites. The ANOVA results showed that the most influential parameters on wear loss and coefficient of friction were the content of B4C with 51.35% and the normal load with 45.54%, respectively. An artificial neural network was applied for the prediction of wear loss and the coefficient of friction. Two separate networks were developed, both having an architecture of 3-10-1 and a tansig activation function. By comparing the predicted values with the experimental data, it was demonstrated that the well-trained feed-forward-back propagation ANN model is a powerful tool for predicting the wear behavior of Al2024-B4C composites. The developed models can be used for predicting the properties of Al2024-B4C composite powders produced with different reinforcement ratios and milling times. [ABSTRACT FROM AUTHOR]

The wear performance of the ultrahard B 4 C–SiC–TiB 2 ceramic composite was investigated in unlubricated sliding contact in various friction pairs with other ceramics of very different mechanical properties (diamond, Y 2 O 3 -stabilised ZrO 2 , Al 2 O 3 , Si 3 N 4 , and borosilicate glass) under otherwise identical contact conditions. It was found that this composite is, due to its ultra-high hardness (∼35(1) GPa), a promising material for tribological applications (sliding-wear resistance of the order of 105–108 (N·m)/mm3) that undergoes only very mild two-body abrasion against diamond (∼6.5(7)·10−9 mm3/(N·m)) and mild three-body abrasion against ZrO 2 , Al 2 O 3 , Si 3 N 4 , and borosilicate glass (10−6–10−7 mm3/(N·m)). It was also found that the B 4 C–SiC–TiB 2 composite wore faster against Si 3 N 4 (∼3.1(3)·10−6 mm3/(N·m)) than against Al 2 O 3 (∼1.8(3)·10−6 mm3/(N·m)), next against borosilicate glass (∼1.1(1)·10−6 mm3/(N·m)), and finally slowest against ZrO 2 (∼7.2(6)·10−7 mm3/(N·m)), a trend that was justified based on the consideration that its three-body abrasion is a complex phenomenon conditioned by the abundance and hardness of the wear debris, the formation and coherence of protective tribolayers (either oxide or material transfer), and the effective contact pressure acting on the wear debris. Finally, implications arising from the study are presented. [ABSTRACT FROM AUTHOR]

In this work, effect of multi-axial room temperature forging process on scratch and wear characteristics of Al-7.3 and Al-12.1Si alloys with varying cumulative strains was investigated. Al-7.3 and Al-12.1Si alloy ingots were remelted in a furnace and then poured into a preheated die to produce a cast sample of the desired shape and dimension for the MAF process. These samples were subjected to solution heat treatment before forging Scratch test was conducted to measure the scratch resistance of unprocessed and MAF-processed samples. Dry sliding wear tests were performed on a tribometer (pin-on-disk) at ambient temperatures. MAF-processed materials exhibited better scratch and wear resistance compared to as-cast materials. After MAF, wear mechanisms in both alloys shifted from adhesive and delamination wear to a combination of abrasive and a lesser amount of adhesive wear. Moreover, the degree of delamination significantly decreased after MAF-process. Improved scratch and wear resistance is mainly due to increased microhardness via refinement and improved uniformity in the redistribution of eutectic silicon as well as the strain hardening of the aluminum phase. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The main motivation of this work is to use ceramic microspheres (CMs) as a potential filler in polyamide 6 (PA6) to enhance its mechanical and tribological performances. Polyamide 6 composites bearing CMs in different weight ratios (10%–40%) are processed by melt blending and characterized primarily by tensile and bending test, dynamical mechanical analysis, and ball-on-disc wear test. This work clearly shows that the addition of CMs gives rise to superior mechanical and wear resistance contribution to PA6. The tensile strength, tensile modulus, flexural strength, and flexural modulus of the composites are enhanced up to 11%, 25%, 37%, and 80%, respectively, over those of the pristine polymer. The wear resistance of 40 wt% CMs containing composite is 60% higher than that of pure PA6. Consequently, it has been found that CMs can be a suitable alternative especially in applications where mechanical strength is desired due to its advantages of high rigidity and sliding wear resistance. [ABSTRACT FROM AUTHOR]

This study presents a novel approach to enhancing the progressive collapse resistance of a fully welded joint (FWJ) by introducing sliding inner cores within the joint, which is referred to as the FWJ with sliding inner cores (FWJS). Two specimens were prepared and designed with additional consideration of composite action of the slab. Quasi-static tests and refined numerical simulations were conducted to analyze the damage mode, deformation behavior, strain distribution patterns, internal forces, and resistance development in both specimens. The test results revealed that the first fracture occurred in the tensile beam flanges for both FWJ and FWJS specimens, whereas the FWJS specimen exhibited delayed crack of the tensile beam flange compared to the FWJ specimen. The FWJS specimen demonstrated better utilization of the catenary mechanism during the flexural–catenary combined stage. Additionally, in the elastic, elastic–plastic, plastic, and flexural–catenary combined stages, the addition of the sliding inner cores in the FWJS specimen significantly enhanced its resistance by 15.6%, 22.3%, 23.4%, and 70.2%, respectively. It is also revealed that the response of the sliding inner core consisted of bending, transition, and full tension stages, which was shown to effectively replace the fractured beam flange in redistributing the internal forces. Based on the analysis of the working mechanism and numerical parametric analysis, optimal values for the 10 design parameters of the FWJS are suggested, and a comprehensive design procedure for the FWJS is proposed. [ABSTRACT FROM AUTHOR]

In this work, the tribological properties of a novel iron‐based self‐lubricating composite as the tribopairs of a plunger pump were systematically studied on an end‐face tribometer, and the tribological mechanism was also revealed. The results show that the wear mechanism of the composite can be ascribed to adhesive wear when the sliding speed is lower than 1.5 m/s. As the sliding speed increases from 1.5 to 2.0 m/s, the wear type transforms to oxidative wear due to the increase of tribo‐oxidation. In addition, the failure criteria of the tribopair composite materials are summarised. When the average coefficient of friction is greater than 0.04, or the wear rate is greater than 9.66 μm3/(N m), the tribopair fails. This offers a valuable reference for industrial application of the tribopairs made from the iron‐based self‐lubricating composite. [ABSTRACT FROM AUTHOR]