Sliding Wear Experiments Research Articles

Wear micromechanics, mechanisms and wear map of Al-12.6Si-0.25Fe-XMn alloy: The role of Al15(Mn,Fe)3Si2 intermetallic and microstructure modification

Abstract The study investigates the microstructural evolution and wear behaviour of Al-12.6Si-0.25Fe-xMn alloys (x = 0, 1, 2, and 3 wt.%) in dry sliding wear experiments. Manganese (Mn) considerably modifies the microstructure by modifying primary and eutectic silicon particles, changing Fe-rich intermetallic compounds, and increasing the overall wear resistance of Al-12.6Si-0.25Fe. The microstructural investigation demonstrates the production of Al15(Mn,Fe)3Si2 intermetallic phases, as well as a more uniform Si particle distribution. Wear experiments at varied loads (20 N, 40 N, and 60 N) show that Mn addition significantly reduces wear rates and specific wear rates, especially at lower loads. The findings highlight Mn's significance in increasing the hardness and wear resistance of Al-Si-Fe alloys, making them better suited to automotive applications.

Directed energy deposition combined with interlayer remelting for improving NiTi wear resistance by grain refinement

Directed energy deposition of NiTi coatings has received much attention, however, its performance is difficult to meet the increasing requirements in the engineering field. In order to refine the grains to improve wear resistance, a novel interlayer remelting method for fabricating NiTi alloys by directed energy deposition is proposed in this study. The influence of laser interlayer remelting parameters on lattice structure, phase transformation behavior, microstructure, crystallographic evolution, and microhardness was thoroughly analysed in comparison. Good formability is demonstrated after interlayer remelting, while the high energy density leads to microstructure refinement and eutectic regions are observed between dendrites. The grain size decreases with increasing remelting speed, which is due to the faster cooling rate having a greater degree of subcooling with more nucleation points. The faster interlayer remelting speed shows a higher microhardness (586 HV0.2) with higher wear resistance, which is attributed to its finer grain size and significant grain boundary strengthening. Reciprocating sliding wear experiments show that the wear resistance is improved after interlayer remelting, especially at a load of 30 N, the specific wear rate is 1.35 * 10−4mm3/Nm, which is only 47 % of that of the untreated sample. This study proposes a technique to achieve synergistic enhancement of microhardness and sliding wear properties of reinforced coatings, which provides a theoretical basis for the application of NiTi coatings in engineering and extends the field of additive manufacturing.

Investigation of tribology and life prediction of polymer coatings on 7N21 aluminum alloy under dry sliding wear

To improve the tribological properties of the 7N21 aluminum alloy under dry sliding wear conditions, three E44-PI-PAI composite coatings filled with varying contents of MoS2, h-BN and VN were designed. The mechanical and tribological performances of these coatings were evaluated using scratch experiments, nanoindentation, and sliding wear experiments. After identifying the optimal coating, the engineering constants of the coating were determined using tensile experiments. Finally, a simulation analysis of the reciprocating wear life was performed using ABAQUS and a custom-developed UMESHMOTION subroutine. The results indicate that the optimal ratio of MoS2, h-BN and VN in the designed polymer coating is 4:3:4. The coefficient of friction (CoF) and wear rate of the optimal coating are 0.189 and 0.444×10−14 m3/Nm, representing a 67 % reduction in CoF compared to the 7N21 aluminum alloy. The L2 coating demonstrates excellent compatibility, featuring a surface roughness (Ra) of 0.630 μm, a uniform thickness of 10±2 μm, an optimal bonding strength at level 0, and a nanohardness of 0.391 GPa, meeting the requirements for engine bearings. The maximum deviation between the simulated wear life prediction and experimental results is only 8.11 %.

TRIBOLOGICAL INVESTIGATION OF TUNGSTEN CARBIDE AND HARD CHROME COATINGS ON EN19 FOR COLD ROLLING APPLICATION

In the heavy sheet metal industry, rolls are generally made up of EN19. To enhance the life of the cold rolling mills it can be coated. This paper presents an experimental study to check the effect of alloy coatings such as Hard Chrome and Tungsten carbide on wear resistance and other characteristics of roller base materials EN19 which is used in rolling process of heavy metal industry. In this paper a comparative tribological study of Hard Chrome, Tungsten carbide, EN19 through hardness testing, surface roughness analysis, SEM, and EDS, XRD, sliding wear experiments and statistical study through Design of Experiment has been performed to find out the best material which can increase the life of rolls. From the experiments carried out it has been found that hardchrome has 15.19 times the longevity of the substrate EN19. Tungsten carbide has 19 times the life of EN19 and 1.25 times the life of hardchrome. Tungsten carbide coating gives more hardness and wear resistance than the Hard Chrome and EN19 base material of the roll. Thus, using Tungsten carbide coating on EN19 rolls will improve the life and enhance the longevity of the roll used in cold rolling process in heavy steel industry.

A comprehensive sliding wear prediction method for planetary roller screw mechanism

The thread-pairs wear has a significant role in the transmission accuracy, operational stability and service life of planetary roller screw mechanism (PRSM). Nevertheless, the previous literatures still lack the investigation on the wear evolution of roller, nut and screw. Hence, an accumulative wear depth (AWD) prediction model is proposed for PRSM with reciprocating motion. The presented model is validated by the measured wear phenomena of thread pairs and the experimental results in the literature. The equivalent sliding wear experiment of PRSM is designed and the sliding wear coefficient of PRSM material is obtained by the equivalent sliding wear experiment. Considering the thread profile error caused by AWD of roller, nut and screw, the load distribution (LD) and sliding velocities on screw-roller (SR) and nut-roller (NR) sides are calculated. More importantly, the interactions between the AWD, LD and sliding velocity are investigated. Furthermore, the effects of axial load on the AWD, sliding velocities in contact regions and load distribution coefficient are analyzed.

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.

Comparative Analysis of Wear Behavior of High Entropy Alloy (TiVNbCrAl) and Ti-based Conventional Alloy (TiNbCrCoAl)

This research examined the relationships between processing, structure, and property at both room temperature and increased temperature for two BCC high entropy alloy (TiVNbCrAl) and Ti-based conventional alloy (TiNbCrCoAl) prepared using standard arc melting. Both alloys have been determined to have the BCC single-phase solid solution structure. To investigate the hardness and tribological behavior and processes at room temperature and above, microindentation and sliding wear experiments were undertaken. Both alloys display comparable friction behavior when sliding at room temperature, with an average steady-state coefficient of friction (COF) of 0.6. When sliding temperatures rise to 302 °C, the average COF for HEA (TiVNbCrAl) has decreased to a lowest value of ~0.4 due to the creation of a persistent tribochemical layer made of Nb and Cr oxides amid the sliding surfaces, which lowers COF. Whereas, COF for Ti-based conventional alloy remains at higher values of ~0.65. Mechanistic wear analyses revealed that the formation of tribofilms with low interfacial shear strength inside the wear tracks was the cause of this. The tribofilms were identified to be mostly constituted by multi-element solid solution oxides, such as Ni2O5, Cr2O3, and NiO2, according to Raman spectroscopy. The Vickers microharness values for Ti-based conventional alloy is about 365±4 HV. Whereas, for high entropy alloy is about 572±12 HV due to the solid solution strengthening.

The influence of Co and SiC on the sintering, microstructure and tribological properties of (Ti1/3Zr1/3V1/3)B2 medium-entropy diboride-based ceramics

The (Ti1/3Zr1/3V1/3)B2(MEB) composite ceramics with various Co and SiC additions were prepared by spark plasma sintering technology at 1600 °C. The influence of Co and SiC on the microstructure and mechanical properties were studied. Reciprocating sliding wear experiments of boride ceramics sliding against GCr15 ceramic were also performed at 1 N, 5 N and 10 N (Temperature: 25 °C, frequency: 3 Hz, stroke: 1 mm). The result suggest that the sintering additives not only significantly reduces the sintering temperature of boride ceramic, but also refines the microstructure and improves its mechanical properties. The hardness and fracture toughness of MEB-20SiC–10Co ceramics are 27.76 GPa and 3.9 MPa m1/2, 30.6 % and 60 % higher than that of MEB, respectively. The increase in fracture toughness results from crack deflection and branching of the SiC particles. Tribological results indicates that MEB-20SiC–10Co also show the best tribological performance. The wear rate of MEB and MEB-20SiC–10Co at 10 N load are 2.17 × 10−6 mm3N−1m−1, 1.29 × 10−6 mm3N−1m−1, oxidative wear and adhesive wear are the main wear mechanisms. Analyzing of the wear tracks revealed a significant transfer of material from the counterpart to the tribo-interface. A friction film consisting mainly of titanium oxide and part of boron oxide was generated on the worn surface, which contributes to the improvement of tribological performance.

Enhancing tribological performance in PM Vanadis 6 steel through optimization of cryogenic and tempering treatment

Vanadis 6, which gained popularity for industrial applications due to increased strength and wear resistance, benefited from cryogenic treatment. This study investigated the influence of cryogenic and tempering treatments on the tribological properties of Vanadis 6 cold-work tool steel, crucial for cost-effective and durable tooling. Dry sliding wear experiments using Taguchi design under varying loads and sliding velocities revealed that cryogenic treatment at − 140 °C followed by 170 °C tempering resulted in the lowest wear rate, friction coefficient, smoothest worn surfaces, and the highest transition load. Microstructural analysis supported these findings, indicating reduced retained austenite and increased carbide count in cryogenically processed steel at − 140 °C.

Effect of salt bath nitriding on tribological properties of AISI52100 steel coatings using RSM

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 ASTM G-99 standard, and the findings show a 30% reduction in wear loss. Sliding wear experiments were conducted at 1.5 meters per sec with a 5 N force at room temperature on uncoated and nitrided pins which was obtained as optimum value from RSM. The three variables five levels central composite design (CCD) were utilized in order to reduce the number of trails and the model relations were examined through ANOVA. Surface hardness, friction coefficient, wear coefficient, Loss in wear is 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 coefficient of friction 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 coefficient of friction.

Sliding Wear Behavior of Pineapple Leaf/Glass Fiber Reinforced Polyester Composites

AbstractIn this work, the effect of the kind of reinforcement on the sliding wear performance of a polyester matrix composite reinforced with glass fiber and pineapple leaf fiber is investigated. The purpose of this study is to ascertain the effects of the type of reinforcement on the sliding wear performance of a polyester matrix composite reinforced with glass fiber and pineapple leaf fiber. By using hot press molding and the 30% weight fraction of fiber reinforcement, polyester composites with four distinct compositions—PPP, GGG, PGP, and GPG—have been created. These composites' dry sliding wear experiment is carried out using a Pin on Disc wear testing device. The following parameters are used in experiments: a track radius of 50 mm, a sliding distance (SD) of 500 m, an applied load of 50, 70, or 90 N, and a sliding velocity of 3.14, 4.71, or 6.28 m s−1. For dedicated (PPP, GGG) and hybrid (PGP, GPG) polyester composites, the effects of load, sliding velocity (SV), and wear rate (WR) are studied. At 50 N and 3.14 m s−1 the COF for PPP and GGG dedicated composites is 0.68 and 0.70, respectively, whereas for PGP and GPG hybrid composites, it is 0.41 and 0.64. The PGP/GPG hybrid composites have a minimal wear rate of 3.34e‐8 m3 s−1 and are 80% more effective than dedicated composites. Utilizing the Analysis of Variance (ANOVA) and Taguchi L9 orthogonal array, regression models are created to optimize the influence of various parameters, such as load, sliding velocity, and composition. Results of confirmation tests show excellent agreement with predictions generated using the developed mathematical model.

Influence of Surface Finish on the Dry Sliding Wear and Electrochemical Corrosion Behaviour of 316L Stainless Steel

316L stainless steel is known for its high corrosion resistance and extensively being used for biomedical implants and for the fabrication of the parts in nuclear reactors, and fuel cells. In the current study, 316L stainless steel samples were grounded using different grades of surface grits (400, 1200, and mirror-finished) by mechanical polishing, and influence of surface finish on the wear and corrosion characteristics was studied. The dry sliding wear experiments were carried out on ball-on-plate setup against hardened steel ball and the corresponding friction curves were obtained and specific wear rates were measured. The wear mechanisms were identified by examining the worn-out surface using scanning electron microscope and Raman spectrometer. It was evident that the formation and removal of iron oxides is the dominant mechanism for material loss from the samples during wear tests. The higher wear resistance of the mirror-finished sample was attributed to the formation of stable chromium oxide layer on the wear track. Potentiodynamic polarization tests were performed on the samples and better corrosion resistance was observed for the mirror-finished sample.

Uncertainty Analysis of Friction and Wear-Rate of Cylinder Liner–Piston Ring Tribo Pair Under Boundary Lubrication Conditions

Abstract Uncertainty analyses can improve the reliability and validity of the assessment of friction and wear-rate of tribosystems. This work analyses the various sources of uncertainty in the estimation of friction and wear-rate of liner-ring pairs using a linear reciprocating tribometer (LRT) as per the analytical method suggested by Guide to the Expression of Uncertainty in Measurement (GUM) and simulation approach using Monte Carlo simulation (MCS) method. The uncertainty analysis was conducted by performing sliding wear experiments using a hypereutectic Al–Si cylinder liner specimen against the chrome-coated piston ring as the counter specimen. The experiments were performed to mimic the engine’s condition under a boundary layer lubrication regime. The type A and type B uncertainty components of the tribosystem, such as uncertainty involved in the measurement of mass, linear dimensions of the specimen, radius of the specimen, normal force, stroke length, and frictional force, were evaluated to study their influence on the assessment of the friction and wear-rate. The probability density function of all these uncertainty sources was simulated using the MCS approach to compute the 95% coverage interval for friction and wear-rate directly. The variation in absolute value between the coverage interval limits computed by the GUM framework and predicted by the Monte Carlo method for wear-rate was 11.83%, and for friction coefficient, it was 12.005%.

Sliding wear characteristics and wear constitutive equation of lead-free white metal under various lubricating liquids

In the present study, sliding wear experiments are conducted on lead-free white metal under three types of lubricating fluids, that is, two types of lubricating oils and water, and the sliding wear characteristics and friction coefficient of the sliding surface of the white metal are investigated. Lubricating fluids were selected with viscosities varying widely from 1.0 × 10−3 to 409.7 × 10−3 Pa s. Based on the experimental results, the constitutive equations of sliding wear, the coefficient of friction, and the effects of lubricating oil viscosity η and compressive stress σ are investigated. The coefficient of friction is proportional to σ0.5 and η−0.5. Therefore, as η increases in the low σ region, the coefficient of friction decreases and the amount of wear decreases. Conversely, as η decreases in the high σ region, the coefficient of friction increases; thus, the amount of wear increases and the sliding surface seizes. Furthermore, a method for quantitatively predicting the sliding wear life of white metals is devised from the perspective of machine maintenance. The wear life required to achieve a certain wear depth can be estimated using the wear constitutive equation proposed by the authors, which is expected to facilitate the safety management of bearings and the extension of their operating life.

Influence of TiC Particles on Mechanical and Tribological Characteristics of Advanced Aluminium Matrix Composites Fabricated through Ultrasonic-Assisted Stir Casting

The present investigation highlights the development of high-performance materials in the construction materials industry, with a special focus on the production of aluminium matrix composites (AMCs) containing titanium carbide (TiC) particles. The stir casting method with ultrasonic assistance was employed to enhance the mechanical and tribological properties. ASTM standards were employed to evaluate the influence of TiC particles on density, hardness (VHN), ultimate tensile strength (UTS), and wear resistance at various TiC weight fraction percentages (0.0 wt.%, 2.0 wt.%, 4.0 wt.%, 6.0 wt.%, and 8.0 wt.%). Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis were performed to analyse the microstructural changes and elemental phases present in the synthesised composite. Results revealed that the incorporation of 8 wt.% TiC reinforcement in the metal matrix composites demonstrated significant improvements compared to the base alloy. In particular, a substantial enhancement in hardness by 32%, a notable increase of 68% in UTS, and a significant 80% rise in yield strength were observed when contrasted with the pure aluminium alloy. The tensile fracture analysis of the specimens revealed the presence of dimples, voids, and cracks, suggesting a brittle nature. To assess the wear characteristics of the composites, dry sliding wear experiments were performed using a pin-on-disc wear tester. Incorporation of TiC particles resulted in a lower coefficient of friction than the base alloy, with the lowest friction coefficient being recorded at 0.266 for 6 wt.% TiC, according to the data. FESEM and energy-dispersive X-ray spectroscopy (EDXS) were used to examine the surfaces of the worn pin. Overall, the inclusion of TiC reinforcement particles in the matrix alloy greatly enhanced the wear resistance and friction coefficient of the Al-6TiC composites. Ploughing and adhesion under lower loads and delamination under higher loads were the wear mechanisms observed in the wear test.

Wear behavior and tribo-surface characteristics of nano magnesium composites

A nano magnesium composite was synthesized with the addition of 5.6 wt.% of titanium, 3 wt.% of aluminum and 2.5 wt.% of nano boron carbide particles through the disintegrated metal deposition process. To validate the metallurgical features of the synthesized magnesium composite, the samples were exposed to X-ray diffraction study and scanning electron microscopic analysis with dispersive spectroscopy analysis. Wear behavior of the nano magnesium composite was studied through pin-on-disc dry sliding wear experiments by changing the load and sliding velocity over a sliding distance of 3000 m. Further, wear rate of the produced material was analyzed for varied wear parameters. Wear behavior of the magnesium composite revealed an adverse effect with an increased load and a positive effect with increased sliding velocity. The microscopic analysis of the worn surface and the collected debris revealed the characteristics of the wear surface of the nano magnesium composite. Adhesion, abrasion, delamination, oxidation and thermal softening were the mechanisms observed in the post-failure analysis.

Friction and Wear in Stages of Galling for Sheet Metal Forming Applications

Aluminum is a very commonly used material at present, and roughly half of the produced aluminum products undergo forming during manufacturing. Galling is a severe form of wear that occurs during sheet metal forming operations and is a common failure mode of materials in sliding contact; however, the causes and mechanisms of galling are poorly understood. In this work, sliding wear experiments were conducted to produce galling wear between a tool steel ball bearing and aluminum alloy Al5083, to study the relationship between the coefficient of friction, the lump growth on the tool and the scratch morphology. Whilst the characteristic friction regimes were observed, the characteristic damage (grooves running parallel to the scratch direction) was not observed. Instead, when galling was developed on the indenter, the scratch surface morphology displayed a series of peaks and grooves perpendicular to the scratch direction. It is likely that the difference in scratch morphology observed once galling was initiated is due to the lower hardness and reduced work hardening behavior of the Al5083 alloy, compared to the high strength steels previously examined in sheet metal forming applications. The evolution of the scratch morphology has been characterized in a novel way by investigating the distribution of the longitudinal cross-section profile height along the scratch length in relation to the three-stage friction regime observed. This showed that, as the galling wear progressed, the longitudinal cross-section profile height distribution shifts towards negative values, with a corresponding shift in the distribution of material transferred to the tool shifting to the positive. This indicates that, as the amount of material adhered to the indenter increased, the depth of the grooves on the scratch surface perpendicular to the sliding direction also increased.

High temperature sliding wear behavior of detonation sprayed Ni-5wt%Al coating

The tribological behavior of detonation (DSC) sprayed Ni-5%wtAl coatings at room temperature (25 °C) and elevated temperature (850 °C) has been studied in this work. Dry sliding wear experiments were done by using alumina (Al2O3) ball-on-disc tribometer. FESEM-EDS and a non-contact 3D profilometer microanalysis were used to evaluate the worn scar and wear rate and identify the wear mechanism. X-ray diffraction (XRD) investigation indicated that the Ni-5wt%Al coating predominantly consists of γ-Ni phases at 25 °C and 850 °C conditions. The phase evolution, thermal expansion, crystallite size, and lattice strain were evaluated using in-situ high-temperature X-ray diffraction (HT-XRD). The crystallite size (D) and lattice strain (ε) were determined by Williamson-Hall analysis using a uniform deformation model (UDM), employing X-ray peak profile analysis (XPPA). In high-temperature conditions, the thermal expansion mismatch between the coating and substrate is negligible, with reduced spallation and cracking at the interface. The findings of the wear tests revealed that as the temperature increased, the coefficient of friction (CoF) and wear rate (ω) significantly decreased as the wear mechanism changed from abrasive to adhesive. The improvement of wear resistance of Ni-5wt%Al coating at high temperatures has been evaluated and discussed from the perspective of thermal expansion and tribo-layer formation.

Mechanical and tribological assessment of AA7075 reinforced Si3N4/TaC/Ti hybrid metal matrix composites processed through stir casting process

ABSTRACT In the present research work, microstructural, mechanical and tribological aspects of Aluminium alloy (AA) 7075 reinforced with Titanium (Ti), Tantalum Carbide (TaC), and Silicon Nitride (Si3N4) ceramic particles were explored by utilising stir casting. Mechanical attributes like compression, tensile, hardness and flexural were evaluated. Dry sliding wear experiments at both room (30°C) and elevated atmospheric (60°C & 120°C) conditions were conducted to investigate the wear performances. Microstructural analyses reveal homogeneous distribution of reinforcements in the matrix along with good interfacial bonding with negligible amount of agglomeration. Considering the effect of hard ceramic materials in the matrix alloy tensile, compression, flexural and hardness of the developed MMCs found to be improved when compared with base alloy. Finer grains restrict the dislocation movement due to the Orowan strengthening mechanism of the developed hybrid MMCs. As the force enhances from 20 N to 40 N, the rate of wear for AA7075 reinforced with 0.75 wt% TaC, 6 wt% Si3N4, and1 wt% Ti was found to be minimum. Taguchi and Analysis of Variance (ANOVA) were performed to acquire the optimum process and dominating parameters. Regression analysis showed the relationship between the output and input control factors.

The impacts of retained austenite on the microstructure and property changes of carbide-free bainite during sliding wear

With the rapid development of Chinese railway industry, there is an increased demand for better toughness, wear resistance and fatigue resistance of wheel/rail materials, and the development of carbide-free bainitic wheel/rail materials with stable and outstanding comprehensive properties is of great significance to the acceleration of railway development. This paper conducts sliding wear experiment on the currently developed FCB bainitic wheel steel (abbreviated as FCB in the following content) and AB1 bainitic rail steel (abbreviated as AB1 in the following content), and investigates the impacts of retained austenite (RA) on the microstructure and property changes of carbide-free bainite. During the process of sliding wear, the wear morphology of FCB is chiefly featured by abrasive wear; As wear rotations increase, adhesion wear and fatigue wear gradually appear. Compared with AB1, FCB with similar chemical composition has more RA, which causes it to undergo plastic deformation more easily during sliding wear. The deformation gives rise to higher strain in the surface layer and makes the grains caused by it much smaller, leading to white etching layers (WELs) with higher thickness and hardness more easily. Meanwhile, more RA means that more martensite phase with high thickness will be generated during the wear process, which increases the hardness of FCB. These two factors work together to make wear resistance of FCB better.