Friction Wear Research Articles

Effect of Ni–Bi Alloying on the Microstructure and Self‐Lubricating Properties of CoCrNi‐Based Coatings Across a Wide Temperature Range

This study investigates the use of bismuth (Bi) as a lubricating additive in laser cladding Co‐based composite coatings, addressing the issue of Bi segregation and agglomeration through Ni–Bi alloying. The microstructure, mechanical properties, and tribological properties of composite coatings with varying Ni–Bi contents are systematically evaluated at temperatures between 30 and 800 °C. Analysis reveals that Ni and Bi elemental powders are successfully alloyed to form BiNi and Bi3Ni intermetallic compounds following vacuum sintering. Incorporation of Ni–Bi alloying powder significantly enhances the friction coefficient and wear rates of the composite coating across the temperature range. Adhesive wear and abrasive wear are identified as primary wear mechanisms. Notably, the formation of BiNi, multiple oxides, and Bi16CrO27 compounds on the surface of the 85:15 (at%) Bi:Ni composite coating at 600 °C created a self‐lubricating friction layer, synergistically reducing friction. Consequently, compared to Co‐based alloy coatings without Ni–Bi alloying, the composite coating exhibited a three‐fold reduction in friction coefficient and a two‐order‐of‐magnitude improvement in wear rate, demonstrating exceptional tribological properties.

Investigation of tribological performance of PAI and PAI/graphite/PTFE composites under different mediums and working conditions

Purpose This study aims to investigate the tribological performance of neat polyamide-imide (PAI) and PAI composite (PAI + 12% graphite + 3% polytetrafluoroethylene [PTFE]) under varying mediums and conditions, including dry sliding, distilled water and seawater lubrication, to determine their suitability for high-stress applications. Design/methodology/approach Tribological tests were conducted using a pin-on-disc setup with AISI 316 L stainless steel (SS) as counterface. Experiments were carried out under loads of 150 and 300 N and sliding speeds of 1.5 and 3.0 m/s. Values of temperatures, friction coefficients and wear rates were recorded to analyze the effect of fillers and lubrication mediums. Findings The PAI composite outperformed the neat PAI under all conditions, showing significant reductions in friction coefficients and wear rates. Seawater lubrication yielded the best results, achieving friction coefficients of 0.05 and 0.01 and specific wear rates of 18.10−16 m²/N and 1.10 −15 m²/N, for neat PAI and PAI composite, respectively. Graphite and PTFE fillers enhanced lubrication, reduced surface temperatures and mitigated abrasive and adhesive wear mechanisms. Superior cooling and lubrication effects of the seawater contributed to these improvements. Originality/value Previous studies mainly focused on dry sliding and distilled water lubrication for the PAI and its composites, with no research on the seawater conditions. This study compares the tribological behaviors of the neat PAI and PAI composite against AISI 316 L SS under dry sliding, distilled water and seawater lubrication. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0302/

Lubricating Performance of Lanzhou Lily Crude Extract as Natural Additive

Due to environmental concerns and multifunctional requirements, natural additives are a promising alternative to traditional enhancers like metal nanoparticles. Lanzhou lily crude extract (LLCE) was investigated as an additive in PEG400 base oil. Firstly, different contents of LLCE as an additive notably improved physiochemical properties, such as thermal stability, viscosity, and the viscosity index. With 5–10 wt.% of LLCE added in PEG400, the thermal degradation temperature increased by 37.3–49.5 °C. Secondly, the addition of LLCE significantly reduced the friction coefficient and wear rate of the steel disc at 50–150 N compared to pure PEG400 base oil with a reduction degree of up to 30% and 92%. The optimum additive content was 7 wt.%, and further increasing the content of the additive did not bring about obvious improvements, even worsening the product in some cases. Thirdly, the lower friction coefficient and wear rate achieved through the addition of LLCE may be due to the higher viscosity facilitating a thicker lubricating film and the higher polarity providing better chemical affinity with the metallic surface. In summary, LLCE is a promising additive that significantly improves the physicochemical properties and lubricating performance of PEG400 base oil.

Effect of Laser Energy Density on the Microstructure and Mechanical Properties of Al2O3/Inconel 718 Nanocomposites Fabricated by SLM

Metal-matrix nanocomposites (MMNCs) with high performance have broad application prospects. Selective laser melting (SLM) was employed to fabricate Al2O3-reinforced Inconel 718 nanocomposites. The influence of laser energy density (E) on the microstructure and properties of the materials was thereafter investigated. The results show that the microstructure and mechanical properties of the composite can be significantly improved by optimizing E. When E increased from 219 J/mm3 to 288 J/mm3, the size of the Al2O3 reinforcement reduced, and the average grain diameter of the matrix was found to decrease from 1.09 μm to 0.22 μm. Additionally, the relative density improved from 89.82% to 97.04%. When the laser energy density is 288 J/mm3, the sample exhibits favorable hardness and wear resistance. The average microhardness of samples with 288 J/mm3 reaches 379.32 HV0.5 Compared with 219 J/mm3 sample, the increase is 15.01%. The average friction coefficient and wear rate decreased to 0.24 and 3.75 × 10−4 mm3/N·m, respectively. Notably, compared with the samples with E of 219 J/mm3, these values reduced significantly by 60.65% and 60.15%, respectively. The study results can provide technical support for the production of MMNCs with high performance by SLM in industry.

Tribological performance of modified graphene as an additive in copper wire drawing lubricant

Purpose This study aims to explore the use of modified graphene (MG) in copper wire drawing lubricants to enhance their friction-reducing and anti-wear capabilities. Design/methodology/approach Graphene was modified using oleic and stearic acids to improve its dispersibility in lubricants. Various concentrations of MG were then introduced into a copper wire drawing lubricant to investigate their tribological performance. Wear mechanisms were evaluated with scanning electron microscopy, optical microscopy, Raman spectroscopy and energy dispersive spectroscopy (EDS). Findings The best concentration of MG is 1.5 Wt.%, at which the copper wire drawing oil exhibits a friction coefficient and wear rate of 0.085 and 2.11 × 10−6 mm3/Nm, respectively, representing decreases of 22.7% and 47.6% compared to the base oil. It was further found that the addition of 1.5 Wt.% MG to a copper wire drawing fluid with a water content of 70% resulted in a 30.3% reduction in friction coefficient compared to the base oil. Raman spectroscopy and EDS analysis confirmed that the MG tribo-film formed on the worn copper disc effectively minimized friction and wear. Originality/value This study analyzes the tribological performance of different concentrations of MG in copper wire drawing oils, establishing a basis for the application of MG in copper wire drawing fluids. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2024-0399/

Enhanced Tribological Performance of Laser-Textured TiN-Coated Ti6Al4V Alloy Surfaces: A Comparative Study with Untextured Surfaces

Titanium alloy is widely used as a biomaterial due to its strength, lightweight nature, and corrosion resistance. Despite its strength and lightweight nature, its low wear resistance limits its uses in prosthetic components. Laser surface texturing (LST) was used to improve the wear resistance of titanium alloys by creating textured surfaces before applying protective coatings. A biocompatible TiN composite protective coating was applied using physical vapour deposition (PVD) with a thickness of 4 µm. Response surface methodology (RSM) was used to predict the tribological properties by varying input parameters such as material type (TI, T2, T3, and T4), load in N, and sliding velocity in m/s. A pin-on-disc tribometer was used to conduct a unidirectional sliding wear test based on the RSM design. Tribological properties were studied to determine the impact of laser texturing on the bonding strength of the coating. As a result, material type T4 exhibits an improved coefficient of friction and specific wear resistance under varying sliding velocity and load conditions compared to other material types. The study was further supported by an ANSYS simulation, which revealed stress reduction affecting the coefficient of friction and, consequently, wear. The textured surface topography, wear mechanisms, and coating compositions were examined using scanning electron microscopy.

Effect of laser remelting on the microstructure and properties of an AlCoFeNi eutectic high-entropy alloy fabricated through double-wire arc additive manufacturing

Additive manufacturing (AM) technology is a new method for preparing eutectic high-entropy alloys (EHEAs). The resulting EHEAs have excellent mechanical properties. However, in engineering, material failure, such as wear or fatigue fracture, often occurs on the surfaces of components. There is no report on surface modification and strengthening of additively manufactured EHEAs. Therefore, this study successfully utilized laser remelting (LR) technology to enhance the surface properties of an AlCoFeNi EHEA fabricated by using double-wire arc AM technology. After LR, the distance between adjacent regular eutectic regions and lamellar spacing of the EHEAs significantly decreased, and the proportion of strictly semicoherent face-centered cubic/body-centered cubic interfaces increased. When microhardness increased from 277.7 HV to 302.3 HV, the average friction coefficient and wear rate of the alloys decreased by 32.5% and 51.1%, respectively, and hardness and wear resistance significantly improved. This study has laid a solid foundation for the engineering application of the combination of LR and AM and also provided new ideas for improving the surface performance of additively manufactured EHEAs.

Production of Honeycomb-Patterned Hybrid Ti2AlN/TiNi Films and Examination of Mechanical, Tribological, Adhesion and Fatigue Properties

Honeycomb-patterned hybrid Ti2AlN/TiNi films were produced on M2 and Inconel 718 substrates using a magnetron sputtering system. These films were subjected to heat treatment at 750°C. In the XRD patterns of annealed films, crystalline formations corresponding to the Ti2AlN MAX phase (honeycomb edge) and super elastic TiNi (honeycomb inner) films were achieved. Mechanical properties were separately determined for each film area due to the honeycomb-patterned hybrid Ti2AlN/TiNi films having two different film areas. The film deposited on Inconel 718 exhibited the highest hardness values, with 10.2 GPa for the TiNi film and 25.4 GPa for the Ti2AlN film. Considering the results of wear tests performed both at room temperature and at high temperature, it was detected that the friction coefficients and wear rates of the films decreased by at least 50% at high temperatures. Upon examining the adhesion performance of the films, the critical load values for the films deposited on M2 and Inconel 718 were 21 N and 26 N, respectively. According to the multi-pass scratch test results, it was observed that the film deposited on M2 maintained its structural integrity under a load of 7N and exhibited better fatigue performance. This study proved that multi-coating components with different geometric architectures can be produced in a single layer. It also showed that such hybrid coatings exhibit good performance in machine components operating under various service conditions.

Biodegradation and mechanical performance of Silane-chitosan-graphene oxide composite coating on AZ31 magnesium alloys for biomedical applications.

Biodegradable magnesium alloy medical implants have attracted considerable interest thanks to their remarkable biocompatibility and mechanical properties. However, the rapid corrosion rate of magnesium alloys in physiological environments presents a major challenge to their practical application. Therefore, this study attempted to design a silane/chitosan /graphene oxide composite coating that reduces the corrosion and enhances the biodegradation of magnesium alloys used in temporary implants. The composite fabrication process adopted a cost-effective spin-coating technique providing a uniform coating of magnesium alloy substrates. Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) results showed a dense and compact silane/chitosan/graphene oxide (Silane/CS/GO) coating on the magnesium coated alloy surface. The mechanical properties of the fabricated silane/chitosan/graphene oxide composite were also investigated by microindentation and scratch tests. The hardness of the magnesium alloy increased from ~268HV ±13.4 to ~644.13HV±32.2 upon the application of the coating. Moreover, the results showed that the cohesive critical load (LC) of the ternary composite was greater than LC~3.02±0.15N. In addition, compared to uncoated AZ31 alloys, the friction coefficient and wear volume of the ternary composite decreased from ~0.13±0.02 to ~0.07±0.004 and from ~18 to ~0.04 (106μm3), respectively. Finally, the corrosion of the composite coating was assessed in simulated body fluid (SBF) in vitro at 37°C. Hydrogen evolution results revealed that graphene oxide seemed to delay the diffusion of corrosive ions into the Mg matrix, while Silane prevented the coupling of GO graphene oxide sheets to the metal surface. Consequently, silane / chitosan /graphene oxide composite coatings could be a very useful material for coating magnesium implant devices. It contributed to reduce the corrosion of the substrate and alleviate the cost and discomfort of implants.

Wear Properties and Characterization of T15 High‐Speed Steel Prepared by Hot Isostatic Pressing, Forging, and Vacuum Heat Treatment

Effect of heat treatment (HT) on T15 high‐speed steel (HSS) prepared by hot isostatic pressing (HIP) and forging processes using electrode induction melting gas atomization powder is successfully studied; their microstructure, friction, and wear properties are in comparison. The lowest friction coefficient and wear rate are achieved in the forging plus HT T15 HSS. Simultaneously, the minimum wear profile depth and dimension are also obtained in the forging plus HT one. The prior particle boundaries produced by HIP are overtly eliminated, and the grains are refined and evenly distributed after forging and HT processes. The refined microstructure after forging plus HT promotes improvement of friction and wear performance. Wear mechanisms for samples prepared by different processes are discussed. The microstructure is characterized by high‐angle angular dark field‐scanning transmission electron microscopy, scanning electron microscopy, and white light interferometer. This work proves that HSS products with high wear properties can be prepared by appropriate HIP + forging + HT processes.

Microstructure and tribological performance of ceramic-based self-lubricating sealing coating on a composite substrate

This work used high velocity oxygen fuel spraying technology to prepare three types of ceramic-based self-lubricating sealing coating on C/SiC substrates, with Yttria-stabilized zirconia as the matrix and different mass fractions of Mo and Ag as lubricating phases. The compositions are S1(50%YSZ40%CaF210%Mo), S2(50%YSZ40%CaF210%Ag) and S3 (40%YSZ30%CaF210%Mo10%Ag10%SiO2). The friction coefficient and wear rate of the coating were examined at room temperature (RT), 400°C and 800°C. The effects of different lubricating phases on the tribological properties of the coating were compared. The wear mechanism of the coating under different temperature environments will be revealed by clarifying the evolution law of the microstructure of the coating. The results show that the addition of Ag can improve the lubricating ability of the coating. Ag element forms a continuous and smooth tribo-layer on the sliding surface to reduce the friction coefficient of the coating. In addition, the lubricating effect of Ag element is more significant at medium and low temperatures. At 800°C, the S3 coating with both Ag and Mo exhibited excellent tribological properties. The wear mechanism of the coating is that it starts with adhesive wear and gradually transitions to abrasive wear as friction continues. This work provides theoretical support and experimental evidence for the construction of ceramic-based self-lubricating sealing coating with a wide temperature range.

Modification of the Surface Layer of Grey Cast Iron by Laser Heat Treatment

This paper presents possible modifications to the properties of grey cast iron by laser heat treatment. These modifications are analyzed especially with regard to wear properties as a result of graphite content, which is a well-known solid lubricant. Examples of applications of grey cast iron in cases where good wear resistance is required are presented. Laser hardening from the solid state, laser remelting, and laser alloying are characterized. In this study, changes in the surface layer caused by these treatments were analyzed (especially the influence on the microstructure—including graphite content—and wear properties). It was shown that all of these treatments enable the wear resistance of the surface layer to be enhanced, mostly due to the increase in the hardness and microstructure homogeneity. It was also proven that it is possible to retain the graphite phase (at least partially) in the modified surface layer, which is crucial in the case of friction wear resistance. In particular, laser hardening from the solid state does not eliminate graphite. Laser remelting and alloying cause the dilution of carbon from the graphite phase to the melted metal matrix, but, in the case of nodular cast iron, it is possible that not all of the valuable graphite in the surface layer is lost.

Improved Friction Reduction and Wear Resistance of Steel Using a Subnanometer Nanowires-Poly-α-Olefin Gel Lubricant.

Lubricating oil is commonly utilized due to its excellent lubricating properties in mechanical motion systems. However, high fluidity in lubricating oil often leads to leakage during machine operation, causing mechanical components to fail. Herein, a gel lubricant of SNWs-PAO6 was devised by combining subnanometer nanowires (SNWs) with poly α-olefin 6 (PAO6) at room temperature, effectively confining PAO6 and preventing PAO6's creeping and leakage while enhancing its load-bearing capacity. SNWs-PAO6 outperforms PAO6 in reducing friction and wear for steel-on-steel interfaces. The friction coefficient is markedly diminished by 57.53%, from 0.223 to 0.095, while the wear rate is significantly curtailed by 84.98%. Furthermore, SNWs-PAO6 remains stable even after 180 000 cycles at 200 N and 25 Hz, withstanding high-speed centrifugation without releasing PAO6. It remained stable over 6 months of resting and can well withstand low temperatures. Surface analysis of the wear scar and the formed tribochemical film after friction has demonstrated that PW12O403- is more likely to adsorb onto the steel surface, forming a lubricating medium film through tribochemical reactions and thus reducing interfacial friction and wear. This method facilitates the development of domain-limited nanomaterials-based gels for mass production and their applications in engineering moving parts.

The Effect of Post Heat Treatment on the Microstructure and Mechanical Properties of Cold-Sprayed Zn-6Cu Deposits.

To explore the feasibility of preparing Zn alloy bulk, Zn-6Cu deposit was prepared by cold-spraying additive manufacturing. Microstructure, tensile and wear behavior were investigated before and after heat treatment. Cold-sprayed Zn-6Cu deposit was constituted by irregular flattening particles and pores after heat treatment. Zn-6Cu deposits were composed of Zn and CuZn5 phases in addition to ZnO phase regardless of heat treatment, but the full width at half maximum of both the CuZn5 and the Zn phase were varied. The yield strength and ultimate tensile strength of Zn-6Cu deposits after post heat treatment were, respectively, increased from 83.8 ± 28.7 MPa and 159.6 ± 44.5 MPa to 89.4 ± 24.4 MPa and 223.8 ± 37.1 MPa. Fracture morphology after tensile testing exhibited main features of dimples, pores and cleaving particles. The friction coefficient and wear rate of Zn-6Cu deposits were increased after heat treatment, and the corrosive wear exhibited a lower friction coefficient and wear rate than the dry wear due to the lubricant of simulated body fluid. Grooves and localized delamination were the main wear features of Zn-6Cu deposits regardless of both the heat treatment and wear condition. This result indicates a potential application of cold-sprayed Zn-6Cu deposits comparable to the casting ones.

Effect of Counterbody Material on the Boundary Lubrication Behavior of Commercially Pure Titanium in a Motor Oil

Titanium possesses many useful properties and is a technologically important material in engineering. However, lubrication of titanium has long been a problem that has prevented titanium from being more widely used. This is due to its poor tribological properties, deriving from its high tendency towards adhesive wear, material transfer, and abrasive wear. Lubrication is a system engineering which involves material combinations, material surfaces, lubricants, and operating conditions as a system. In this work, the boundary lubrication behavior of commercially pure titanium (CP-Ti) sliding against various counterbody materials in a motor oil (0W-30) was investigated under ball-on-plate reciprocating sliding conditions. The counterbody materials (balls) include CP-Ti, ceramic (Al2O3), steel (AISI 52100), and polymer (nylon). The results show that depending on material combination, the lubricating behavior can be divided into three categories, i.e., (1) lubrication failure (Ti-Ti), (2) improved lubrication but with friction instability (Ti-Al2O3), and (3) effective lubrication (Ti–steel and Ti–nylon). Lubrication failure of the Ti-Ti pair leads to high and unstable friction and severe wear from both the plate and ball, while friction instability of the Ti-Al2O3 pair leads to friction spikes and high wear rates. Effective lubrication of the Ti–steel pair results in low and smooth friction and much-reduced wear rates of the Ti plate by nearly 10,000 times. However, there is a load-dependence of the lubrication effectiveness of the Ti–steel pair. Although the Ti–nylon pair is effectively lubricated in terms of much-reduced friction, the nylon ball suffers from severe wear. The friction and wear mechanisms of the various sliding pairs are discussed in this paper.

Wear characteristics and life extension mechanism of Ti3C2 MXenes nano-lubricated airframe rolling bearings

Under extreme working conditions, airframe rolling bearings are likely to suffer from weakening bearing capacity and fatigue failure due to excessive temperature and poor lubrication. These weaknesses are expected to be improved by using two-dimensional layered nanomaterials MXenes, which exhibit excellent lubrication performance, thermal conductivity and mechanical strength. In this study, Ti3C2 MXenes is added into the lubricating grease of airframe rolling bearings. The friction coefficient and temperature rise comparison tests of rolling bearings lubricated with the MXene additives lubricating grease (MALG) and original lubricating grease (OLG) are carried out on the high-performance rolling bearing comprehensive test rig. The wear morphologies of rolling bearings lubricated with MALG and OLG under the same working condition are compared by a white light interferometer. The wear characteristics and life extension mechanism of MXene nano-lubricated airframe rolling bearing are analyzed. The results show that MALG can effectively reduce the friction coefficient and suppress the temperature rise of bearings compared to OLG. Meanwhile, MALG demonstrates superior anti-wear properties compared to OLG under extreme conditions. Notably, under the condition of 2000 rpm, 6KN and 20% grease filling volume, compared to the rolling bearing lubricated with OLG, the friction coefficient, temperature rise and wear areas of those with MALG are reduced by 18.89%,48.64% and 67.50%, respectively. This study proves the beneficial contribution of MALG in the practical engineering application of bearings, which provide valuable reference for extending the service life of aerospace bearings under extreme conditions.

Utilization of Magnetic Fraction Isolated from Steel Furnace Slag as a Mild Abrasive in Formulation of Cu-Free Friction Composites

Magnetic fraction isolated from steel furnace slag was tested as a component of Cu-free friction composites. The friction–wear performance and production of wear particles during their testing using a pin-on-disc tester against a cast iron disc were evaluated. To compare the effect of the magnetic fraction on the parameters studied, the composite with alumina and the composite with original steel furnace slag were also prepared and tested. All composites showed a comparable friction coefficient. The composite with original steel furnace slag, and the composite with a magnetic fraction showed higher wear resistance compared to the composite containing alumina. The positive effect of the magnetic fraction on the extent of the emission of wear particles was observed and explained by the decreased aggressiveness of this composite to the cast iron disc. The influence of the phase composition of the steel furnace slag and the magnetic fraction on the friction film formation was also indicated, and its effect on the production of wear particles was proposed.

Microstructure and tribological performances of laser cladded FeCoCrMoSi amorphous coating under different normal loads

Purpose The aim was to investigate the effect of normal load on the tribological performance of laser cladded FeCoCrMoSi amorphous coating, which might choose the appropriate normal load for the friction reduction and wear resistance. Design/methodology/approach A FeCoCrMoSi amorphous coating was prepared on 45 steel using laser cladding, and the tribological performance of obtained coating under the different normal loads was investigated using a ball-on-disk tribometer. Findings The FeCoCrMoSi amorphous coating is composed of M23C6, Co6Mo6C2 and amorphous phases, where the M23C6 hard phase enhances the coating hardness to increase the wear resistance and the Co6Mo6C2 with the vein shape forms the strong mechanical interlock to play the role of friction reduction. The average coefficients of friction of containing amorphous FeCoCrMoSi coating under the normal loads of 3, 4 and 5 N are 0.68, 0.65 and 0.53, respectively, and the corresponding wear rates are 17.7, 23.9 and 21.9 µm3•N−1•mm−1, respectively, showing that the appropriate normal load is beneficial for improving its friction reduction and wear resistance. The wear mechanism is composed of adhesive wear, abrasive wear and oxidative wear, which is attributed to the high hardness of amorphous coating by the amorphous phase. Originality/value The FeCoCrMoSi amorphous coating was first applied for the improvement of 45 steel, and the effect of normal load on its tribological performance was investigated. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0304/

Friction Behaviors and Wear Mechanisms of Carbon Fiber Reinforced Composites for Bridge Cable.

Carbon fiber reinforced epoxy resin composites (CFRP) demonstrate superior wear resistance and fatigue durability, which are anticipated to markedly enhance the service life of structures under complex conditions. In the present paper, the friction behaviors and wear mechanisms of CFRP under different applied loads, sliding speeds, service temperatures, and water lubrication were studied and analyzed in detail. The results indicated that the tribological properties of CFRP were predominantly influenced by the applied loads, as the tangential displacement generated significant shear stress at the interface of the friction pair. Serviced temperature was the next most impactful factor, while the influence of water lubrication remained minimal. Moreover, when subjected to a load of 2000 g, the wear rate and scratch width of the samples exhibited increases of 158% and 113%, respectively, compared to those loaded with 500 g. This observed escalation in wear characteristics can be attributed to irreversible debonding damage at the fiber/resin interface, leading to severe delamination wear. At elevated temperatures of 100 °C and 120 °C, the wear rate of CFRP increased by 75% and 112% compared to that at room temperature. This augmentation in wear was attributed to the transition of the epoxy resin from a glassy to an elastic state, which facilitated enhanced fatigue wear. Furthermore, both sliding speed and water lubrication displayed a negligible influence on the friction coefficient of CFRP, particularly under water lubrication conditions at 60 °C, where the friction coefficient was only 15%. This was because the lubricant properties and thermal management provided by the water molecules, which mitigated the frictional interactions, led to only minor abrasive wear. In contrast, the wear rate of CFRP at a sliding speed of 120 mm/s was found to be 74% greater than that observed at 60 mm/s. This significant increase can be attributed to the disparity in sliding rates, which induced uncoordinated deformation in the surface and subsurface of the CFRP, resulting in adhesive wear.

Comparative Study on the Wear Characteristic and Control Method of Rail Corrugation in Typical Fastener Sections

This paper conducts a comparative study on the severity, development trends of rail corrugation, and the suppression effects of rail vibration absorbers on small-radius curved track sections supported by two types of typical fasteners. Firstly, a finite element model (FEM) of the wheel-rail system for small-radius curved track sections is established based on field investigation data. Then, a comparative analysis is conducted on the frictional coupling vibration characteristics and wear characteristics of the rail surface for wheel-rail systems in the two typical fastener sections. Additionally, the suppression effect of installing rail vibration absorbers on rail corrugation is analyzed. The results indicate that the frictional coupling vibration in the wheel-rail system is the primary cause of rail corrugation on small-radius curved track sections, and the vibration response of the wheel-rail system in the Cologne egg fastener section is significantly greater than that in the DTVI2 fastener section. Furthermore, rail corrugation in the Cologne egg fastener section is more severe and develops faster compared to the DTVI2 fastener section. Finally, the installation of vibration absorbers suppresses rail corrugation in both fastener sections, with a more pronounced suppression effect observed in the Cologne egg fastener section.