Wear Of Composites Research Articles

Tribological behavior of poly(ether ether ketone)/synthetic Eucommia rubber composites

AbstractOur previous study (Polymer Composites 2023, 44: 1252–1263) revealed the positive role of rubber in modifying the tribological properties of polymer composites. This concept was applied here by incorporating synthetic Eucommia rubber (TPI) to 3D printed polyether ether ketone (PEEK) skeletons with different infill densities. The formation of TPI/PEEK composite improved the friction and wear of PEEK matrix with some reduction in mechanical performance. The composite with 70% infill density is recommended in terms of its overall performance. Based on the morphological and chemical analysis, the composite's wear mechanism was discussed. The findings of this present study could pave a new route to modify friction‐reduction and anti‐wear performance of PEEK.Highlights Novel composites were successfully prepared from thermodynamically incompatible synthetic Eucommia rubber (TPI) and polyether ether ketone (PEEK). The tribological properties of TPI/PEEK composites were studied in association with the infill density of PEEK. The TPI rubber helped improve the friction and wear properties of PEEK thanks to its role in enhancing the formation of transfer films on the counter steel surface.

Tribological, mechanical, and thermal properties of nano tricalcium phosphate and silver particulates reinforced Bis-GMA/TEGDMA dental resin composites

The proposed study is based on fabricating a hybrid dental composite of nano tricalcium phosphate and silver nanoparticles with resin matrix. Silver nanoparticles (20 wt%) and tricalcium phosphate (0–4 wt%) were incorporated in Bis-GMA/TEGDMA resin matrix. Photo initiator and accelerator were also employed for the polymerization of dental composites. Wear or tribology analysis of dental composites was performed on pin on disc setup. Physical, thermal, and mechanical properties were investigated under ASTM parameters. Void, water solubility, and sorption increased with an increment of filler loading. Maximum polymerization shrinkage 3.85 ± 0.02 % and depth of cure 2.57 ± 0.12 mm indicated by control sample TAg0. Taguchi L25 orthogonal array was used as a design of experiment (DOE) for wear analysis. TGA revealed the thermal stability in the form of: TAg0 > TAg1 > TAg2 > TAg3 > TAg4 in the range of 22–100 ̊C. In conclusion, the direct restorative material composed by the hybrid showed good mechanical and physical properties and potential thermal results, widening the scope of Ag and tricalcium phosphate in the dental composites.

Microstructural and mechanical properties of Al-Al2O3 micro and nanocomposite fabricated by stir casting

ABSTRACT The current study examines the relationship between the microstructure and tribological characteristics of Al-Si alloy composites reinforced by secondary phase nano SiC particulates synthesis via the stir casting process. The results of wear testing of stir-cast SiC metal matrix composites including up to 12 weight percent fine (75–100 µm) and coarse (125–150 µm) size particles were obtained from cast aluminium alloy. It was discovered via microstructural investigation that the aluminium alloy and SiC particles have good interface bonding. However, at greater amounts (12 wt.%) of fine size reinforcement, clustering of reinforced particles is observed. In addition, results state that finer size particles agglomerate more in the matrix than coarser size particles at greater reinforcement levels. In addition, increasing the amount of SiC particles in the matrix enhanced the hardness of the base alloy. However, when the size of the SiC particles was reduced, the hardness of the composite increased dramatically. Better wear resistance was observed for higher SiC reinforcement levels, while higher forces were also associated with a corresponding increase in wear rate. A combined mode of adhesive and abrasive wear mechanisms is responsible for composite wear, according to a scanning electron microscopy (SEM) investigation of worn surfaces.

Microstructure and high-temperature tribological behaviours of nano-HfC reinforced Inconel 625 composite coating by plasma-transferred arc welding

The study involved plasma arc transfer welding (PTAW) for preparing coatings of Inconel 625 alloys that contained different amounts of nano-sized hafnium carbide (nano-HfC) particles. The impact of nano-HfC on the microstructure evolution and mechanical properties of PTAWed Inconel 625 were investigated. The research reveals that nano-HfC decomposes during the high-temperature plasma arc process and then react with O element to generate nano-HfO2. These HfO2 can serve as nucleation sites for MC carbides, which restricts the growth of secondary dendrite arms, leading to a more disordered grain growth direction. Simultaneously, the decomposition of HfC can increase the C/Nb ratio of the matrix, effectively suppressing Laves phase formation while encouraging the development of MC carbides. Compared with IN625, the wear rate of composites at room temperature and 600 °C were decreased. Notably, at 600 °C, the wear rate of the coating with 0.5 wt% HfC is the lowest among all the samples, as reflected by a noteworthy reduction in wear rate of 50 %. This is mainly attributed to the refinement of γ matrix, reduction of Laves phase as well as precipitation of the fine-sized MC carbides. This work illustrates that adding nano-HfC is an effective way to improve the wear resistance of the PTAWed Inconel 625.

Regulating the severe running-in wear of polymer composites by a dual-pin-on-disk (DPOD) multicomponent approach

Polymer composites are increasingly used as frictional components due to their self-lubricating properties. However, they tend to exhibit severe wear during the running-in stage, thus significantly impairing their service life. In the present work, a dual-pin-on-disk (DPOD) method is developed in order to reduce the running-in wear of a polytetrafluoroethylene/alumina (PTFE/Al2O3) composite when sliding against GCr15 bearing steel by introducing an assistant polymer component during the running-in stage. The results show that the running-in wear rate of the main polymer pin is reduced by up to 77.26 %. This is because the assistant pin causes excess wear debris to be released into the wear track and provides a higher shear force, thereby promoting the tribological chemical reactions and facilitating the generation of tribofilms on the worn surfaces. In addition, the processed polymer achieves a wear rate similar to that of the conventional single pin condition (∼3 × 10−7mm3/Nm) in the subsequent steady-state stage. The results of the present work are expected to increase significantly the wear life span and application prospects of the polymer composites.

Study on the Wear Behaviour of Aluminium foam Reinforced Glass Fibre Epoxy Composites

Hand layup was used to fabricate the glass fibre reinforced aluminium foam epoxy composites in this study. On the manufactured materials, dry sliding wear experiments were performed. The effect of wearprocess parameters such asapplying load (kg), speed (m/s), and sliding distance (m) on specific wear rate (Ws) was investigatedand the obtained results were compared with neat glass fibre reinforced epoxy composite in this work. The outcome of these results showed that specific wear rate (Ws) of glassfibre epoxy composite containing aluminium foam decreased as compared with neat glass fibre reinforced polymer composites. Experimental results showed that a minimum wear rate of 10.1 �m was attained for the sliding velocity (1.5 m/s), Applied load (2 kg), and sliding distance (1000 m) in the fabricated composite laminates. It was observed thatthe resistance to wear in glass fibre reinforced aluminium foam composite was mainly due to the bond strength between aluminium foam and epoxy.

Determination of “tribological performance working fields” for pure PEEK and PEEK composites under dry sliding conditions

Poly-ether-ether-ketone (PEEK) and PEEK composites are widely used polymers in many engineering applications where dry sliding is required. In this study, the influence of sliding velocity and applied load values on the friction and wear behavior of pure PEEK, 30 wt% glass fiber reinforced PEEK (PEEK-30GF), 30 wt% carbon fiber reinforced PEEK (PEEK-30CF) and 10 wt% carbon fiber+10 wt%graphite +10 wt%poly-tetra-fluoro-ethylene (PTFE) filled PEEK (ie. High (H) pressure (P) and velocity (V) resistant PEEK (PEEK-HPV)) composites rubbing against AISI 304 stainless steel disc was investigated. The experiments were carried out at room temperature under dry sliding conditions in a pin-on-disc wear rig. The applied loads ranged from 30 to 250 N, while the sliding velocities ranged from 1.0 to 4.0 m/s. At these load and velocity ranges, the friction coefficient-wear rate relationship of pure PEEK and composites was established and evaluated. In addition, the operating load-velocity limits of each material were determined and stated. The lowest coefficient of friction and wear rate were obtained in PEEK-HPV, PEEK-30CF, PEEK-30GF composites and pure PEEK polymer, respectively. In addition, it was observed that the coefficient of friction (CoF) decreased and the specific wear rate (SWR) increased with the increase in sliding velocity and applied load in all PEEK materials. The wear rate values of PEEK-HPV and PEEK-30%CF composites are in the range of 10−7 - 10−6 (mm3/Nm), while the wear rate values of pure PEEK and PEEK-30%GF are in the range of 10−6 - 10−5 (mm3/Nm). It was determined that carbon fiber, graphite and PTFE additives added to PEEK polymer as hybrid were very effective in reducing the wear rate of PEEK composite (PEEK-HPV). An adhesive wear mechanism was observed in PEEK-HPV and PEEK-30CF composites both at low load and velocity values and at high load and velocity values.

INFLUENCE OF GRAPHITED DUST ON THE ABRASION PROCESSES OF COMPOSITE MATERIAL BASED ON POLYTETRAFLUOROETHYLENE

Purpose. Study of the influence of graphitized dust on abrasive wear of polytetrafluoroethylene-based composites. Research methods. Experimental studies were performed using modern methods of physical and mechanical tests, which ensures the reliability of the results. A laboratory mixer with a rotating electromagnetic field and a hydraulic table press TU 10003 TORIN were used for the production of samples. Weighing of samples for experiments was carried out on a VLR-200 scale, abrasion assessment was carried out on a HECKERT machine. The friction surfaces were studied using a BIOLAM-M microscope. Results. The conducted studies showed that the index of abrasive wear of the composite with a polytetrafluoroethylene matrix decreases from 2.974 mm3/m to 2.539 mm3/m with a content of 10 % of graphitized dust. This helps to increase the service life of parts, which will reduce the frequency of their replacement, as well as reduce production costs. Given that graphitized dust is a waste of metallurgical production, its secondary use as a filler for composite materials allows to partially solve the environmental problem of disposal of production waste. Scientific novelty. Today, the production of products from composite materials is one of the promising directions of production, because the combination of a polymer matrix with various fillers makes it possible to obtain more economically profitable materials, forming the necessary physical properties. The possibility of using production waste as a filler allows solving the current problem of recycling and disposal of environmentally harmful substances. Therefore, the conducted research opens up new ways to solve a complex of environmental and economic problems. Practical value. The obtained results are important in the further process of manufacturing composite materials. The ability to increase the resistance of the material to abrasive abrasion allows the production of parts that work in friction conditions.

Revealing patterns of change in the tribological efficiency of composite materials for machine parts based on phenylone and polyamide reinforced with arimide-t and fullerene

The object of the study is the process of changing tribological efficiency according to tribotechnical characteristics (wear intensity, friction coefficient, temperature in the contact zone) of composites based on phenylone C-1 and polyamide PA-6 with arimide-T filler and fullerene C-60. The study solved the problem of obtaining composites with high wear resistance. Based on the results of research, it was found that varying the content of arimide-T makes it possible to obtain composites with different patterns of changes in tribotechnical characteristics under conditions of dry friction, lubrication with water and I-50 oil. Composites with the composition: phenylone C-1+15 wt. have the maximum tribological efficiency. % arimide-T+3 wt. % fullerene C-60 and polyamide PA-6+30 wt. % arimide-T+3 wt. % fullerene C-60. Phenylone C-1 has destructive properties when working in the environment of water and temperature in the friction zone. Its reinforcement with arimide-T and fullerene C60 gave positive results of a complex of tribotechnical characteristics under these conditions. It was found that the wear of composites based on phenylone C-1 in I-50 oil is two orders of magnitude lower than in water. Research of samples from the obtained composites based on phenylone C-1 and polyamide PA-6, reinforced with the optimal content of arimide-T and fullerene C60, showed that their wear resistance when lubricated with oil is 3.5...4.0 times greater than the wear resistance of bronze. An applied aspect of the reported results is the introduction of manufacturing technologies and restoration of machine parts from the proposed composites. It has been proven that their optimal composition contributes to high tribological efficiency and could provide the required level of wear resistance and reliability of resource-determining nodes, systems, and machine assemblies. The results could be used by machine-building and repair-technological enterprises

Influence of betel nut fiber hybridization on properties of novel aloevera fiber-reinforced vinyl ester composites

Abstract This work presents the influence of betel nut fiber hybridization on the properties (mechanical, thermal, wear, and water absorption) of novel aloevera fiber-reinforced vinyl ester composites. In this research, we fabricated the composites by changing the wt.% of aloevera fiber and betel nut fiber through the hand layup method using the compression molding technique. From the results, it has been observed that increases in wt.% of betel nut fiber increased the mechanical properties, thermal properties, wear resistance, and water resistance of the composites. The composite with the designation S1 shows the lowest hardness, tensile, flexural, impact, and shear strengths of 49.58, 26.59 MPa, 52.53 MPa, 4.12 J, and 101.26 MPa, respectively. Meanwhile, the composite with the designation S5 shows the highest hardness, tensile, flexural, impact, and shear strengths of 71.29, 62.61 MPa, 78.24 MPa, 9.57 J, and 139.52 MPa, respectively. Further, higher wear resistance and water resistance were obtained by the S5 specimen. SEM analysis shows the good strength of betel nut fiber and enhances the tensile strength of the composites.

Extraction of Lignin from Fluorescent Perianths of Jack Fruit and it’s Mechanical, Wear, Creep and Flammability Behaviour of Abaca-Polyester Composites

Extraction of Lignin from Fluorescent Perianths of Jack Fruit and it’s Mechanical, Wear, Creep and Flammability Behaviour of Abaca-Polyester Composites

Mechanical, wear and thermal properties of natural fiber-reinforced epoxy composite: cotton, sisal, coir and wool fibers

Natural fiber-reinforced epoxy composites (NFRCs) have gained significant attention in recent years due to their potential as environmentally friendly and sustainable materials. These composites combine natural fibers, derived from plants, with epoxy resins to create a material with enhanced properties. The objective of this study is to investigate the mechanical, wear and thermal properties of NFRCs incorporating cotton, sisal, coir and wool fibers. The vacuum-assisted resin transfer molding (VARTM) technique was employed to produce composite plates, followed by conducting tests on tensile, wear and thermal properties. The cotton composite showcased the highest tensile strength, reaching 52.81 MPa, while the coir composite exhibited the lowest, measuring 15.34 MPa. Sisal composite exhibited a moderate wear rate (1.423 mm3/Nm) and a lower coefficient of friction (0.233), implying smoother relative motion. Coir composite presented the highest wear rate (4.615 mm3/Nm), attributed to its coarse fiber nature. Thermal conductivity is highest at cotton composite (1.017 W/mK) and is lowest at coir composite (0.187 W/mK). Additionally, the highest specific heat was observed in the coir composite (26.313 MJ/m3K). Cotton demonstrated potential for efficient heat transfer, while wool outperformed in insulation. Sisal displayed versatility for structural applications. Coir emerged as an effective insulator with energy-saving applications.

The Impact of nanoparticles (B4C-Al2O3) on mechanical, wear, fracture behavior and machining properties of formwork grade Al7075 composites

This study explores how ageing temperature and the volume percentage of Al2O3+B4C nanoparticles influence the machinability and hardness of stir-cast Al-7075 Metal Matrix Composite (MMC). Using liquid metallurgy techniques, hybrid materials were created by reinforcing Al7075 metal matrix with varying weight percentages of nanosized B4C (1.5%, 3%, and 4.5%) and Al2O3 (1%, 1.5%, and 2%). After fabrication, the samples were subjected to five-hour ageing process at temperatures of 100, 120, and 140 degrees Celsius, followed by cooling to ambient temperature (27 degrees Celsius). Hybrid nano composites that had been heat treated were tested for wear, tensile strength, and hardness. Results shows that, the addition of nanoparticles and heat treatment considerably improves the tensile strength, hardness, and wear resistance of hybrid composites by 3%, 17%, and 10%, respectively, for samples reinforced with 4.5% B4C + 2% Al2O3. SEM analysis was used to investigate the type of wear and the tensile fracture mode of nano composite samples by analyzing the wornout surface and the surface where tensile fracture occurred. Machinability was assessed using L27 orthogonal array tests, focusing on three key process parameters: feed rate (0.1 mm/min), depth of cut (0.2 mm/min), and spindle speed (1000 rpm). Outcomes show that, increasing the wt. % of nano-Al2O3/B4C leads to higher machining force and surface roughness (Ra) of MMCs. Conversely, higher ageing temperatures result in decreased machining force and surface roughness. Optimal surface roughness and machining force were achieved with 1% Al2O3 + 1.5% B4C and an ageing temperature of 140°C. These findings offer valuable insights into the ease of machining of composite metal alloys, emphasizing the importance of parameter selection and optimization for desired machining outcomes.

Tribological synergy of copper‐based metal–organic frameworks, carbon fibers and SiO2 in modifying the friction and wear properties of epoxy composites

AbstractCopper‐based metal–organic frameworks is anticipated to find applications in the field of friction materials owing to its plentiful surface‐active groups and distinctive framework structure. In this study, copper‐based metal–organic frameworks was synthesized through ultrasound‐assisted method and incorporated alone into carbon fiber reinforced epoxy composites or together with SiO2 nanoparticles towards the goal of improving the composites' friction and wear properties. It is revealed that copper‐based metal–organic frameworks alone cannot improve the friction and wear of carbon fiber reinforced epoxy composites simultaneously. The combination of copper‐based metal–organic frameworks and SiO2 nanoparticles was more effective in enhancing both the mechanical and tribological properties of studied composites. The composite material exhibits a friction coefficient of 0.104 under the specified test conditions of 10 MPa and 3.75 m/s. Additionally, the specific wear rate is impressively low, measuring only 5.64 × 10−7 mm3 N/m. Through morphological and chemical analysis on the worn surfaces and transfer films, the functioning mechanism of copper‐based metal–organic frameworks in modifying the mechanical and tribological properties was discussed. It was discovered that a tribological synergy exists between short carbon fibers, copper‐based metal–organic frameworks, and SiO2 fillers, leading to a shift in the wear mechanism of the composite materials from abrasive wear to adhesive wear. Concurrently, a shear‐prone transfer film forms on the surface of the counter steel surfaces. Findings of the present study pave a new route of designing high performance epoxy based tribo‐composites by using metal–organic frameworks.Highlights Cu‐BDC nanosheets were synthesized using ultrasound‐assisted techniques and incorporated as tribological fillers in EP composites. The combined use of Cu‐BDC, SiO2, and SCF fillers synergistically enhances the mechanical and tribological properties of EP composites. The composite material exhibits a friction coefficient of 0.104 under the specified test conditions of 10 MPa and 3.75 m/s, the specific wear rate is impressively low, measuring only 5.64 × 10−7 mm3N/m. During the sliding friction process of the composite materials, Cu‐BDC and SiO2 play a crucial role in reducing SCF pull‐out wear through their anchoring effect. The dynamic coordination bond structure of Cu‐BDC contributes to the formation of uniform and continuous transfer films on counter metal surfaces.

The Microstructure, Mechanical, and Friction-Wear Properties of Boron Carbide-Based Composites with TiB2 and SiC Formed In Situ by Reactive Spark Plasma Sintering.

The paper presents the influence of the temperature of the sintering process on the microstructure and selected properties of boron carbide/TiB2/SiC composites obtained in situ by spark plasma sintering (SPS). The homogeneous mixture of boron carbide and 5% vol. Ti5Si3 micropowders were used as the initial material. Spark plasma sintering was conducted at 1700 °C, 1800 °C, and 1900 °C for 10 min after the initial pressing at 35 MPa. The heating and cooling rate was 200 °C/min. The obtained boron carbide composites were subjected to density measurement, an analysis of the chemical and phase composition, microstructure examination, and dry friction-wear tests in ball-on-disc geometry using WC as a counterpart material. The phase compositions of the produced composites differed from the composition of the initial powder mixture. Instead of titanium silicide, two new phases appeared: TiB2 and SiC. The complete disappearance of Ti5Si3 was accompanied by a decrease in the boron carbide content of the stoichiometry formula B13C2 and an increase in the content of TiB2, while the SiC content was almost constant. The relative density of the obtained boron carbide composites, as well as their hardness and resistance to wear, increased with the sintering temperature and TiB2 content. Unfortunately, the reactions occurring during sintering did not allow us to obtain composites with high density and hardness. The relative density was 76-85.2% of the theoretical one, while the Vickers hardness was in the range of 4-12 GPa. The mechanism wear of boron carbide composites tested in friction contact with WC was abrasive. The volumetric wear rate (Wv) of composites decreased with increasing sintering temperature and TiB2 content. The average value of coefficient of friction (CoF) was in the range of 0.54-0.61, i.e., it did not differ significantly from the value for B4C sinters.

Experimental investigations with machine learning techniques for understanding of erosion wear in advanced aluminum nanocomposites

This article addresses the significant challenge of erosion wear in aluminum composites, particularly in industries such as automotive, aerospace and energy, where sustained material performance is crucial. The study focuses on the experimental investigation of erosive wear characteristics exhibited by advanced aluminum nanocomposites, utilizing an air jet erosion wear test apparatus. The erosion wear tests were conducted using diverse parameters, such as angles (30°, 45°, 60° and 90°), air pressures (1–4 bar) and a fixed 600-s duration, maintaining a constant sand particle feed rate of 2.0 (g/min) and utilizing stand-off distances of 10, 15 and 20 mm. Surface assessments were conducted using field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS). The results revealed observable specimen wear, particularly at a 45° angle, with wear rates decreasing at higher impingement angles and reaching a minimum at 90°. Notably, the Al-4 wt.%TiC nanocomposites exhibited a 25% improvement in wear resistance compared to the base alloy. Further analysis of eroded surfaces through (FE-SEM) revealed a mechanism involving micro-cutting, plowing and grain pull-out, attributing wear primarily to plastic deformation and crack formation. Evaluating erosive wear results through six machine learning (ML) models demonstrated that gradient boosting regression emerged as the most accurate, achieving an R2 value of 0.97. This highlights the effectiveness of ML in predicting erosion wear rates and offers insights for improving aluminum composite materials in demanding industrial applications.

EFFECT OF CRAB SHELL ASH (CSA) REINFORCEMENT ON SLIDING WEAR CHARACTERISTICS OF AL-7075 COMPOSITES

This study examines the sliding wear behavior of aluminium 7075 composites supplemented with crab shell ash (CSA), a waste product from the seafood industry. The composites with different weight percentages of CSA (0%, 1%, 2%, and 3%) were created using the stir-casting procedure. Afterward, a pin-on-disc device was used to evaluate these composites under different sliding conditions. The primary aim of this research is to analyze the effects of CSA content and sliding parameters on composite wear performance. In the experiment, it was discovered that the stability of the composites differed depending on the amount of CSA that was present. The unreinforced aluminum 7075 alloy's wear resistance was enhanced with CSA particles, according to the data. Wear resistance is optimal at 3% CSA content and begins to decline somewhat above this concentration. As a contribution to sustainable material engineering, this study is significant since it improves metal matrix composites' properties by reusing waste materials. This research emphasizes the potential of using waste materials such as crab shell ash to enhance mechanical properties and wear resistance, to promote sustainability in material engineering approaches.

Mechanical, wear, thermal conductivity and hydrophobicity behavior of Kevlar fiber-epoxy structural composites reinforced with onion peel carbon quantum dot and commercial carbon nanotubes: a comparative study

Mechanical, wear, thermal conductivity and hydrophobicity behavior of Kevlar fiber-epoxy structural composites reinforced with onion peel carbon quantum dot and commercial carbon nanotubes: a comparative study

Improve the thermal properties of oil‐loaded polysulfone microcapsules by optimizing copper layer for self‐lubricating polyamide

AbstractThis work reports polymer/metal double‐shell microcapsules with polysulfone (PSF) and copper as walls for application in self‐lubricating polymer. First, polyalphaolefin 40 (PAO40) was selected as lubricant oil, and PAO@PSF single shell microcapsules were prepared. A critical issue for the formation of copper layer is the sensitization of PSF shell, which can affect not only the adhesion between PSF shell and copper layer, but also the density of copper layer. The sensitization conditions were discussed in detail, and the corresponding effect on the formation of copper layer was evaluated. PAO@PSF/Cu microcapsules obtained under optimal sensitization condition were characterized by scanning electron microscopy (SEM), thermogravimetric analyzer (TGA), x‐ray energy dispersive spectrometer (EDS) and fourier transform infrared spectroscopy (FTIR). A uniform and compact copper layer improved the thermal properties of microcapsules. PSF/Cu microcapsules maintained relatively complete spherical shape when were heated to 300°C, while the PSF microcapsule softened and deformed at 200°C. The self‐lubricating polyamide 6(PA6) composites containing PAO@PSF/Cu microcapsules were fabricated at 230°C, microcapsules maintained complete structure and uniform distributed in the polymer matrix. Coefficient of friction (COF) and wear rate of PA6 composites were tested under different friction conditions. Compared with pure PA6, 15 wt.% PAO@PSF/Cu microcapsules could reduce the COF by 79.5%, and the wear rate was decreased by 98.3% under 300 rpm sliding speed and 50 N friction load.Highlights PSF/Cu double‐shell oil‐loaded microcapsules were designed and prepared. The copper layer effectively improved the thermal properties of microcapsules. The self‐lubricating PA6 composite exhibited excellent tribological properties.

High-temperature dry sliding friction and wear behavior of in-situ (Al3Zr+ZrB2)/AA6016 aluminum matrix composites

Aluminum alloy, a lightweight material, has poor friction and wear properties at high temperatures. Therefore, aluminum matrix composites were prepared by in-situ autogenous method to enhance the high-temperature friction and wear capability of aluminum alloys. (ZrB2+Al3Zr)/AA6016 in-situ aluminum matrix composites were prepared by in-situ reaction with the addition of mixed salts of potassium fluoborate (KBF4) and potassium fluozirconate (K2ZrF6). The materials were characterized by XRD, SEM, and EBSD. The friction and wear properties were investigated mainly by high-temperature friction and wear experiments combined with SEM and XPS. The results show that the wear resistance of (ZrB2+Al3Zr)/AA6016 aluminum matrix composites far exceeds that of their alloys under severe conditions of high temperature. The wear of AMCs first decreases and then increases with increasing temperature. The lowest wear rate was observed at an ambient temperature of 100°C, where the wear rate of AMCs was reduced by a factor of 2.7 compared to that of aluminum alloys. In addition, the enhancement effect of hard and heat-resistant particles was also due to the oxide film generated during friction on the abrasive scar surface layer of AMCs under this condition and the self-lubricating substance (H3BO3). The composite wear mechanism of AMCs was dominated by abrasive, oxidative, and adhesive wear as the test temperature increased.