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This study focuses on the production of functionally graded composites by utilizing magnesium matrix waste chips and cost-effective eggshell reinforcements through centrifugal casting. The wear behavior of the produced samples was thoroughly examined, considering a range of loads (5 N to 35 N), sliding speeds (0.5 m/s to 3.5 m/s), and sliding distances (500 m to 3500 m). The worn surfaces were carefully analyzed to gain insights into the underlying wear mechanisms. The results indicated successful eggshell particle integration in graded levels within the composite, enhancing hardness and wear resistance. In the outer zone, there was a 25.26% increase in hardness over the inner zone due to the particle gradient, with wear resistance improving by 19.8% compared to the inner zone. To predict the wear behavior, four distinct machine learning algorithms were employed, and their performance was compared using a limited dataset obtained from various test operations. The tree-based machine learning model surpassed the deep neural-based models in predicting the wear rate among the developed models. These models provide a fast and effective way to evaluate functionally graded magnesium composites reinforced with eggshell particles for specific applications, potentially decreasing the need for extensive additional tests. Notably, the LightGBM model exhibited the highest accuracy in predicting the testing set across the three zones. Finally, the study findings highlighted the viability of employing magnesium waste chips and eggshell particles in crafting functionally graded composites. This approach not only minimizes environmental impact through material repurposing but also offers a cost-effective means of utilizing these resources in creating functionally graded composites for automotive components that demand varying hardness and wear resistance properties across their surfaces, from outer to inner regions. [ABSTRACT FROM AUTHOR]

In today's manufacturing industries, Metal Matrix Composites (MMCs) are in high demand owing to their valuable properties like high strength-to-weight ratio and resistance against wear. This research evaluates the wear properties of AA2219 matrix composites reinforced using varying amounts (2%, 4% and 6% by weight) of Si3N4 particles, fabricated by squeeze casting. Wear performance testing of the developed Aluminium Matrix Composite (AMC) is executed by utilising pin-on-disc equipment subjected to varying conditions of load and speed. The wear rate is reported to rise with increasing normal load and sliding velocity. The study also reveals that the wear rate reduces with increasing reinforcement content. [ABSTRACT FROM AUTHOR]

In a current scenario, light weighted composites are the prime need of manufacturers in aerospace, automotive, marine and other applications due to their excellent properties compared to traditional materials. The current study includes the fabrication of Al Alloy 7068-based composites reinforced with Si3N4 nanoparticles by 0.5 to 2.0 wt. % by maintaining a difference of 0.5 wt. % through stir casting approach advanced with ultrasonic treatment. The effect of reinforcement on the tensile behaviour of casted samples was analyzed in terms of ultimate tensile strength, and ductility. The wear performance of casted samples was analysed in terms of volumetric weight loss and COF under the effect of applied pressure, sliding velocity and sliding distance. On the investigation of tensile strength, 1.5 wt. % nanocomposite is the optimum one beyond which agglomeration starts which affects the strength. Wear loss increased with applied stress, sliding velocity and sliding distance. COF also increased with sliding distance but decreased with applied stress. There is a significant increment in seizure pressure noticed with reinforcement addition. Adhesion is the dominant wear mechanism observed during sliding, whereas mixed (adhesion and abrasion) type of wear is noticed for 2 wt. % at higher applied pressure and distance. [ABSTRACT FROM AUTHOR]

The durability of a metallic biomaterial to withstand weight loss is a key factor in determining its service life and performance. Therefore, it is essential to create biomaterials with high wear resistance to ensure the biomaterial has a long service life. Thus, this study aims to explore the dry and wet sliding wear characteristics of the developed Ti-15Mo-xSi as-cast alloys (where x equals 0, 0.5, 1, 1.5, and 2 wt.%) in order to assess the impact of the Si addition on the microstructure, mechanical properties, and wear resistance and to consider them for biomedical applications. The wear experiments were conducted using a pin-on-desk wear testing machine at a load of 20 N and a sliding distance of 1000 m with and without applying simulated body fluid (SBF). Different techniques were utilized in the evaluation of the developed Ti-15Mo-xSi alloys. The results showed that significant grain refining was attained with the Si addition. The hardness, compressive strength, and wear resistance of the Ti-15Mo-xSi as-cast alloys increased with the increase in Si content. The Ti-15Mo-2Si as-cast alloy exhibited the highest dry and wet wear resistance of all the Ti-15Mo-xSi alloys. The worn surfaces were investigated, the roughness and main features were reported, and the wear mechanisms were also discussed. [ABSTRACT FROM AUTHOR]

Industrial technology has been significantly developed, and the high performance and precision machines are desired. Friction and wear are the important factors to achieve the development. Mechanical machines consisting of the parts have usually mating surfaces, and friction and wear on the surface affect the product performance and life. Therefore, friction and wear phenomena must be considered at the design stage to design a machine that has long life and high performance. Predicting the surface feature quantitatively and accurately is difficult because the wear phenomena are not cleared yet. There are various methods to predict the worn surfaces, but those methods cannot generate the virtual surfaces randomly. In this study, a generation method of the virtual primary profile curves is proposed in consideration of wear applying wavelet transformation, and the simulated profile curves are verified comparing the actual profiles obtained in actual experiments. [ABSTRACT FROM AUTHOR]

In this article, a new impact-sliding wear test setup was developed to investigate the impact-sliding tribological/wear behavior of manganese (Mn) additive iron-based hardfacings. The effect of increased Mn content from 0 to 13 wt% on the wear characteristics was examined for a constant load of 200 N, 1000 impacts and 50 strokes/min speed. Hardness evaluation tests revealed that the hardness was increased after the impact-sliding wear tests. The worn surfaces of hardfacings/alloys/hardfacing alloys containing 0 and 8 wt% Mn presented a similar mechanism of micro-abrasion, but the damage caused by the abrasion in 8 wt% Mn additive hardfacings was not so effective in comparison to the hardfacing containing 0 wt% Mn. Above 8 wt% Mn addition, oxidative wear became the dominant wear mechanism with the formation of protective tribo-oxide layers and the wear trend exhibited enhancement in the wear resistance of hardfacings. On the other hand, subsurface analysis showed severe damage under the tribo-oxide layer, which revealed that the wear trend is not an exact indicator of wear resistance of the material. Wear behavior of the hardfacings has been successfully correlated with the hardness, morphology of the worn surfaces and subsurfaces. [ABSTRACT FROM AUTHOR]

Acrylonitrile butadiene styrene (ABS), a petroleum-based thermoplastic, is widely used in various industry. It is important to make product costs without reducing the wear characteristics of products. For this reason, over the past 20 years, researchers have focused on improving product performance by reducing material weight. The literature has limited information about the tribological properties of the ABS polymer samples produced with fused deposition modelling. In this study, gyroid-patterned ABS samples with different infill densities (25%, 50%, and 75%) were produced and the effect on the wear properties of the samples was investigated. The main aim of the study is to show the infill density effect on wear and friction performance of the samples and find the coefficient of friction values. So, this study is one of the first studies which investigated wear and friction properties of ABS polymer produced as gyroid pattern with different infill densities. The study might also be used to have an initial information whether ABS polymer can be used in additive manufacturing systems for the joint components. As the performance indicator, diameter deviation, hardness, surface roughness, test temperature, friction coefficient, weight loss, and wearing surface results of the samples were evaluated. The results show that infill density is an important property that effect the tribological and heating characteristic of ABS samples. The friction and heat of the samples increase by increasing infill density. According to the tribological test results, the highest coefficient of friction and friction temperature were reached in the samples with 75% infill density. [ABSTRACT FROM AUTHOR]

This study investigated the microstructure, hardness, tensile and tribological behaviour of a cooling slope Al–Si–Mg alloy following ECAP and T6 heat treatment. The optical and scanning electron microscopes were applied to investigate the microstructure of the as-cast material and heat-treated ECAPed Al–Si–Mg alloy. The dry sliding wear test was tested with three different loads of 10 N, 50 N, and 100 N with constant sliding speed and sliding distance at 1.0 m/s and 9000 m, respectively, using the pin-on-disc tribometer. The hardness and tensile properties were evaluated through microhardness, UTS, and YS measurement for the as-cast Al–Si–Mg alloy, both heat-treated with and without ECAPed alloys. Moreover, wear rate and COF in the Al–Si–Mg alloy with different loads were analysed and linked with microstructural and strength behaviour after the ECAP process. Meanwhile, these analyses of results were correlated with the behaviour of the as-cast Al–Si–Mg aluminium alloy and heat-treated non-ECAPed alloy. Results demonstrated that a combination of ECAP processing and T6 heat treatment improves the mechanical behaviour, while the COF and wear rate are improved at a load of 100 N.

In recent years, many studies have been carried out on the effect of sub-zero treatments on the tribological properties of steels. However, in friction tests performed at different temperatures, the effect of the deep sub-zero treatment is uncertain. This study, it was aimed to increase the wear resistance of CPPU steel at different temperatures (room temperature and 150 °C) with deep subzero process treatment (−150 °C). Friction wear tests were carried out on a pin-on-disc vertical tester according to ASTM standard G99-05. Field emission scanning electron microscopy and atomic force microscopy were used for worn surface analyses. In tests performed at 150 °C, the friction coefficient was reduced by 110.33% and the wear resistance was increased by 101.66% with the sub-zero treatment compared to the conventional heat treatment. The deep sub-zero treatment reduced the adhesive wear. [ABSTRACT FROM AUTHOR]

Digital image processing (DIP) becomes a common tool for analyzing engineering problems by fast, frequent and noncontact method of identification and measurement. An attempt has been made in the present investigation to use this method for automatically detecting the worn regions on the material surface and also its measurement. Brass material has been used for experimentation as it is used generally as a bearing material. A pin on disc dry sliding wear testing machine has been used for conducting the experiments by applying loads from 10 N to 50 N and by keeping sliding distance and sliding speed constant. After testing, images are acquired by using 1/2 inch interline transfer CCD image sensor with 795(H) ∗ 896(V) spatial resolution of 8.6 μ m (H) ∗ 8.3 μ m (V) unit cell. Denoising has been done to remove any possible noise followed by contrast stretching to enhance image for wear region extraction. Segmentation tool was used to divide the worn and unworn regions by identifying white regions greater than a threshold value with an objective of quantifying the worn surface for tested specimen. Canny edge detection and granulometry techniques have been used to quantify the wear region. The results revel that the specific wear rate increases with increase in applied load, at constant sliding speed and sliding distance. Similarly, the area of worn region as identified by DIP also increased from 42.7% to 69.97%. This is because of formation of deeper groves in the worn material. [ABSTRACT FROM AUTHOR]

In this study, two-step stir process was used to synthesis aircraft Al2030 alloy reinforced composites with 3 and 6 weight percentages of B4C particles. This innovative two-step stir casting process improves the wettability of Al2030 and B4C particles. SEM and EDS were used to characterize the microstructures of the Al2030 alloy with B4C composites. Different mechanical features of Al2030 alloy composites were investigated to determine the impact of B4C particle addition on hardness, ultimate strength, yield strength, and ductility. In addition, the wear behavior of the produced Al2030 alloy with B4C composites was investigated utilizing a pin-on-disc apparatus with variable normal load and sliding velocity over a constant 2000 m sliding distance. SEM micrographs demonstrated homogeneous particle distribution, while EDS patterns validated the elements in the B4C reinforced Al composites. The addition of B4C particles increased mechanical characteristics; further improvement was obtained by increasing the weight fraction of B4C particles in the Al2030 matrix alloy. On the other hand, reduced ductility of the composites was observed due to the incorporation of B4C particles in the soft Al matrix. To determine the effect of B4C particles on tensile failure, wear surface of the composites, fractography and worn surface analyses were performed. [ABSTRACT FROM AUTHOR]

This study investigated the microstructure, hardness, tensile and tribological behaviour of a cooling slope Al--Si--Mg alloy following ECAP and T6 heat treatment. The optical and scanning electron microscopes were applied to investigate the microstructure of the as-cast material and heattreated ECAPed Al--Si--Mg alloy. The dry sliding wear test was tested with three different loads of 10 N, 50 N, and 100 N with constant sliding speed and sliding distance at 1.0 m/s and 9000 m, respectively, using the pin-on-disc tribometer. The hardness and tensile properties were evaluated through microhardness, UTS, and YS measurement for the as-cast Al--Si--Mg alloy, both heat-treated with and without ECAPed alloys. Moreover, wear rate and COF in the Al--Si--Mg alloy with different loads were analysed and linked with microstructural and strength behaviour after the ECAP process. Meanwhile, these analyses of results were correlated with the behaviour of the as-cast Al--Si--Mg aluminium alloy and heat-treated non-ECAPed alloy. Results demonstrated that a combination of ECAP processing and T6 heat treatment improves the mechanical behaviour, while the COF and wear rate are improved at a load of 100 N. [ABSTRACT FROM AUTHOR]

The demand for lightweight, high-performance materials has driven significant advancements in magnesium-based materials. However, their practical implementation faces challenges, primarily due to their low wear resistance, especially in industries like automotive, where weight reduction is vital for fuel efficiency. Furthermore, the process of fabricating and assessing wear behavior incurs time and cost constraints. In light of this, machine learning techniques have emerged as a crucial tool for predicting the mechanical properties, wear characteristics, and tribological performance of diverse materials, including magnesium and its composites. Accordingly, the present study aims to integrate experimental results with machine learning techniques. The objective is to predict the wear rate and friction coefficient of Mg/Si 3 N 4 nanocomposites, thus optimizing material design and manufacturing for superior wear performance. Nanocomposites are fabricated through ultrasonic-assisted stir casting, and a dataset of 120 data points is collected using a pin-on-disc tribometer under dry sliding conditions. Five supervised machine learning regression models are employed to predict wear rate and coefficient of friction, with hyperparameter tuning for a fair comparison. Results are evaluated using various statistical metrics, identifying the most effective model for accurate wear behavior prediction. The study also demonstrates improved wear resistance and lower friction coefficients in nanocomposites compared to pure magnesium. This is attributed to the even distribution of Si 3 N 4 nanoparticles and strong interfacial bonding with the matrix. The presence of a mechanically mixed layer further enhances wear resistance under high loads and speeds. Five wear modes are identified, including abrasion, oxidation, adhesion, delamination, and plastic deformation, providing valuable insights into the wear mechanisms. A comprehensive wear map facilitates a deeper understanding of wear behavior. [ABSTRACT FROM AUTHOR]

This paper presents the study of the microstructure, wear properties of spray-deposited and hot compressed Al-35Si and Al-45Si alloys. The microstructure analysis and wear mechanisms of spray formed and as cast alloys were studied by using optical and scanning electron microscope (SEM). The microstructure of the spray-formed alloys showed fine particulate of primary Si and eutectic phases distributed uniformly in the equiaxed Al- matrix. Microstructural refinement was further increased in the hot-compressed alloys. Hardness, dry friction and wear tests were performed on spray formed alloys and compared with as cast alloys. Friction coefficient (COF) and wear rate of the alloys were measured under different applied loads (10–50 N) and sliding velocities of 1 and 1.5 m/s at constant sliding distance of 5000 m. The results indicated that the hardness and wear resistance of spray formed and hot-pressed alloys were considerably high over that of the as cast alloys. The improvements in hardness and wear resistance of spray-formed alloys were mainly attributed to morphology, size and distribution of Si particles induced during spray deposition process. Analysis of worn surfaces by SEM showed dominant wear mechanism of spray-formed alloy was mainly abrasive wear and oxidation wear. [ABSTRACT FROM AUTHOR]

The impact–abrasion–corrosion behavior of three typical wear-resistant steels including low-alloy wear-resistant steel, martensitic stainless steel and Hadfield steel for ball mill liner in simulated acid slurry was studied by impact–abrasion–corrosion test under high impact energy. The structure, mechanical properties and corrosion resistance of the steels have also been characterized. The result showed that the impact–abrasion–corrosion resistance of the martensitic stainless steel was the best under the condition. Further characterization revealed that the damage behavior of the three tested steels was quite different. The damage process has also been discussed by the interaction among impact, abrasion and corrosion behavior. The result is beneficial to provide reference for selection and development of impact–abrasion–corrosion resistant material for ball mill liner working in weakly acidic slurry. [ABSTRACT FROM AUTHOR]

The wear behaviour of WC-Co cemented carbide reinforced with graphene platelets (WC-Co-GPLs composite) was investigated. The tribological parameters as friction coefficient and wear rate were measured using a ball-on-plate configuration with different contact loads. The microstructures and worn surfaces of composites were studied. The WC-Co-GPLs composite exhibits significantly better tribological properties in comparison to the WC-Co which is most evident at contact load of 80 N, where the friction coefficient and wear rate of the WC-Co-GPLs composite are 0.339 and 9.27 × 10−6 mm3·(m·N)−1, respectively. The improvement in wear behaviour of WC-Co-GPLs composite is attributed to the formation of the tribofilm during the wear test and enhancement of mechanical properties of the WC-Co-GPLs composite. The pulled-out GPLs attaches on the worn surface contribute to the formation of tribofilms during tribology test, especially at higher loads. The tribofilms protect the WC-Co-GPLs from wear and guarantee the integrity of the worn surface. [ABSTRACT FROM AUTHOR]

This study employs Taguchi orthogonal design (L9) to optimize the machining parameters of electro-discharge machining (EDM). The aluminum matrix composite (AMC) with 16 wt.% titanium carbide (TiC) and 4 wt.% graphite (Gr) specimen was prepared by stir casting process. This study involves three control parameters with three levels, namely pulse current, voltage and fluid pressure to predict the process response, such as material removal rate (MRR) and surface roughness (SR) of the worn surface. Maximum MRR of 0.1661 g/min was attained for 10 A, 500 V and 15 kgf/cm2 fluid pressure with corresponding roughness of 11.43 μ m and the minimum value of 7.51 μ m was observed for 10 A, 100 V and fluid pressure of 5 kgf/cm2. A regression model was developed and the effect of control parameters on process responses were determined by analysis of variance (ANOVA). According to ANOVA outcome, the machining parameters which control the process response MRR were determined as voltage (47.94%), pulse current (33.19%) and fluid pressure (17.58%). Similarly, the SR was affected by machining parameters voltage (55.17%), pulse current (22.41%) and flushing pressure (21.47%). The optimum machining parameters were predicted and confirmed by conducting experiments with reasonable error of 2.49% and 2.02% for MRR and SR, respectively. Surface characteristics of the machined AMC was analyzed by scanning electron microscope (SEM) to observe the defects like craters, voids, glued debris and recast layers. [ABSTRACT FROM AUTHOR]

The paper reports wear and friction performance of Al-12Si aluminum alloy reinforced with 1.5 wt% submicron boron carbide (B4C) particles. Composite material is fabricated by ultrasonic stir casting process. Microstructural examination is carried out using optical microscopy and field emission scanning electron microscopy (FESEM). Incorporation and agglomeration-free dispersion of B4C particles is detected in the aluminum matrix. Pin-on-disc tribotester is used to evaluate tribological performance of fabricated composite and base alloy under room temperature dry conditions. Nominal contact pressure of 0.707 MPa is applied against EN31 steel counterface, and sliding speeds are varied between 0.25 and 1.25 m/s. Influence of sliding distance is investigated by varying sliding durations from 10 to 40 min at two fixed load-speed (PV) factors of 10 and 25 Nm/s. Worn pin surfaces and collected wear debris are analyzed using FESEM and energy-dispersive spectroscopy to reveal undergoing wear mechanisms. After initial decrease, wear rate increased almost linearly with speed and became twofold at the top speed. Wear rate transition is seen at 0.5 m/s with sliding distance for the applied pressure. Friction coefficient is not influenced significantly with sliding distance for the fixed PV condition. Adhesion and delamination governed the wear mechanism of base alloy while mechanically mixed layer played key role in the wear performance of composite matrix. Improved wear resistance of aluminum matrix is observed due to incorporation of small amount of B4C particulates making the composite better suited for wear-resistant applications than base alloy. [ABSTRACT FROM AUTHOR]

To serve in a corrosive environment, a corrosion-resistant rail steel U68CuCr has been developed in China. In the present study, the wear behavior of U68CuCr was investigated and compared with the commonly used rail steel U71MnG by rolling contact friction tests. The results indicate that the mass loss and wear rate of U68CuCr are smaller than those of U71MnG. The wear rates under the dry condition are smaller than those under the water–oil condition. In addition, the formation of oxide and spalling finally achieves the dynamic equilibrium on the surface of two types of rail steels. However, the duration of the lubricative and protective wear debris layer is longer for U68CuCr. Moreover, the worn surface of U68CuCr is relatively flat, while the wear regime of U71MnG is more severe. The amount and volume of the spalling pits of U68CuCr are smaller. Furthermore, the plastic deformation layers are shallower, and the rolling contact fatigue cracks are shorter for U68CuCr because of the finer pearlitic microstructure. The results prove that the U68CuCr rail steel shows good wear-resistant ability, suggesting its superior suitability for application in high-speed railways in a marine environment. [ABSTRACT FROM AUTHOR]

In this paper, effect of minor additions of magnesium content in the form of master alloys on the high-temperature dry sliding wear behaviour for A356 alloy has been reported. Alloy composition, normal pressures and sliding distances on A356 alloy at constant temperature of 300°C was studied. The cast alloys and worn surfaces were characterized by SEM/EDX microanalysis. The results indicate that the wear rate of A356 alloy increases with an increase in normal pressures and sliding distances in all the cases and decreases when 0.7% Mg is added to A356 alloy. The decrease in wear rate after the addition of Mg is mainly due to changes in microstructure which lead to improvement in mechanical properties. Further, worn surface study indicates that the formation of iron-rich oxide layer between the mating surfaces during sliding improves sliding wear performance. [ABSTRACT FROM AUTHOR]

The formation of transfer layer especially in polymer‐based composites is unavoidable and essential to investigate the effectiveness of transfer layer under working conditions as it decides the material removal between mating parts. The main aim of the present work is to analyze the performance of transfer layer on specific wear rate (SWR) and coefficient of friction (COF) during dry sliding of hexagonal boron nitride (h‐BN)/prosopis juliflora (PJ) reinforced polymer matrix composite. The mechanical test results exhibited that 136.4%, 145.7%, and 106.2% improvement in hardness, tensile and flexural properties of the hybrid composites compared to pure epoxy. Pin on disc wear test results showed that 15 wt% of h‐BN and 5 wt% of PJ reinforced hybrid composite produced better wear performance of minimum COF as 0.0912 and SWR as 0.0000151 mm3/Nm. ANOVA analysis results showed that load is major contributing parameter on COF and SWR and their percentage of contribution as 25.40% and 79.38% respectively. Worn surface analysis revealed that the reason behind transfer layer formation and its effectiveness under sliding conditions. The major wear mechanisms are identified as micro cutting and micro plowing followed by matrix crack, fiber debonding, and fiber pull out. [ABSTRACT FROM AUTHOR]

To enhance the interfacial bonding between the graphene oxide nanoplatelets (GONs) and epoxy (EP) matrix, two different types of silane coupling agents (amino‐ and EP‐silane) were applied to the GONs‐EP nanocomposites. The effects of the silane compound type and silanized GON loading (0.1–0.5 wt% at an interval of 0.2) on the dry‐sliding wear response of GONs‐EP nanocomposites were then studied. The wear tests were conducted under 20 N load and 1000 m sliding distance. The results showed that the wear properties were remarkably improved by the incorporation of silanized GONs to the matrix, and the best wear behavior was obtained at 0.3 wt% silanized GONs. Most importantly, the amino‐silane coupling agent was shown to be more effective in enhancing the wear resistance of the GONs‐EP nanocomposites. After the wear tests, the composite surfaces were studied by scanning electron microscopy to find the predominant mechanisms. [ABSTRACT FROM AUTHOR]

In the current study, we propose a bifractal stratified characterization method to evaluate the surface profile evolution of a plateau honing cylinder liner during the wear process. This method is suitable for the characterization of two-process and worn surface profiles with bifractal and stratified characteristics. We develop a bifractal truncated separation structure function method to calculate the characterization parameters of the proposed method. In particular, the upper- and lower-strata surface profiles are truncated and separated in order to calculate their fractal parameters. Experimental results demonstrate the ability of the proposed method to outperform the traditional fractal method in characterizing the evolution of the plateau honing cylinder liner surface profile during the wearing process. [ABSTRACT FROM AUTHOR]

In this work, a new scratch test method - multi-pass dual-indenter scratch test - is used to estimate the abrasion resistance of C120 steel. This steel is used in the moulds manufacture for injection of plastic materials filled with glass fibres that are very abrasive. Rp3 tools steel, with different work hardening capacity, was used for comparison. The methodology of multi-pass dual-indenter scratch test approaches the real state of abrasion by performing the scratch tests using a high indenter, that generates a stable large pre-scratch with work hardening and a small indenter to assess the wear performance, excluding the geometric effect of the contact. This method is testing the damage formation during the effective scratching process and its interaction with the damage in the deformed surface layer caused by the prior local scratching deformations. In this way, the abrasion resistance of the two hardened steels with different hardness, 59 HRC (C120) and 62 HRC (Rp3) was estimated.

Purpose: This paper aims to focus on studying the addition of nano-tungsten disulfide (WS2) on fretting wear performance of ultra-high-molecular-weight-polyethylene (UHMWPE). Design/methodology/approach: In this study, the effect of WS2 content on fretting wear performance of UHMWPE was investigated. The fretting wear performance of the UHMWPE and WS2/UHMWPE nanocomposites were evaluated on oscillating reciprocating friction and wear tester. The data of the friction coefficient and the specific wear rate were obtained. The worn surfaces of composites were observed. The transfer film and its component were analyzed. Findings: With the addition of 0.5% WS2, the friction coefficient and specific wear rate increased. With the content increased to 1% and 1.5%, the friction coefficient and specific wear rate decreased. The lowest friction coefficient and specific wear rate were obtained with the addition of 1.5% nano-WS2. Continuingly increasing content, the friction coefficient and wear rate increased but lower than that of pure UHMWPE. Research limitations/implications: The research indicated the fretting wear performance related to the content of nano-WS2 with the incorporation of WS2 into UHMWPE. Practical implications: The result may help to choose the appropriate content. Originality/value: The main originality of the research is to reveal the fretting behavior of UHMWPE and WS2/UHMWPE nanocomposites. It makes us realize the nano-WS2 had an effect on the fretting wear performance of UHMWPE. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0151/ [ABSTRACT FROM AUTHOR]

Effects of different stacking sequences covering one external layer of basalt (HB1), three external layers of basalt fabrics (HB3) and three external layers of carbon fabrics (HC3) using epoxy on wear properties were investigated with a reciprocating pin-on-plate configuration under various conditions. Worn surfaces of composites were examined by scanning electron microscopy (SEM). Mechanical properties such as hardness and three point-bending tests were conducted. The wear resistance of composites decreased significantly with increasing speed. The speed was more effective than that of the stacking sequence on the dry wear. The wear resistance of HC3 composite was better than those of the others due to its superior mechanical properties. Furthermore, worn surface's examination exhibited the fiber fracture and oxidative wear for HB1 samples, matrix wear was dominated upon increasing speed for HB3 hybrid composites, but craters and deformed layer covering the mixtures of fibers and resin were evidenced for HC3 hybrid composites. [ABSTRACT FROM AUTHOR]

In order to improve the tribological performance of the physical vapor-deposited AlCrN coatings, molybdenum disulfide (MoS2)/poly tetra fluoroethylene (PTFE) coatings were fabricated on the AlCrN coatings surface through the thermal spraying method. The microstructure, adhesive strength, hardness, and tribological properties were investigated. Reciprocating sliding tests against SiC ball were executed with a ball-on-plate tribometer. Results showed that the adhesive strength between the AlCrN–MoS2/PTFE composite coatings and substrate was increased by about 15% compared with single AlCrN coatings. Compared with the single MoS2/PTFE coatings, the hardness of the AlCrN–MoS2/PTFE composite coatings surface was increased by about 15%. The MoS2/PTFE layer can availably reduce the friction coefficient of single AlCrN layer, and the AlCrN–MoS2/PTFE composite coatings exhibited the lowest and the most stable friction coefficient. In addition, the MoS2/PTFE layer existed on the wear track and accumulated on both the sides, which was the main reason that the friction coefficient was still lower compared with the samples without MoS2/PTFE coatings. [ABSTRACT FROM AUTHOR]

Basalt fabric-reinforced epoxy composites (BFRCs) were fabricated by moulding method, density measurement and three-point bending tests on these materials were carried out. The tribological behaviour of neat epoxy and its BFRCs were focussed under reciprocating sliding against stainless steel plate. The effects of basalt contents and applied loads with respect to neat epoxy were studied under dry sliding conditions. The experimental results showed that the specific wear rate increased considerably with increasing the load. The basalt fabrics improved the tribological properties of the epoxy by reducing the wear rate significantly under specified loads. The load was more effective on the tribology than that of the fiber content. Moreover, an average friction coefficient of composites/steel tribo-pairs, when tested at 160 N load, was measured to be within the range of 0.32 and 0.12 for static and dynamic components, respectively. Furthermore, Scanning Electron Microscpy (SEM) indicated that fracturing and scuffing were exhibited for the epoxy, while a slight abrasive wear was associated with smooth surface, fiber fracture and formation of debris particles were effective for 40 weight fraction (wt.%) basalt fabric (BF) epoxy composites, but crater formation/oxidation, fiber fracture and fiber debonding were the dominant wear mechanism for 60 wt.% BF epoxy composites. [ABSTRACT FROM AUTHOR]

Boron carbide (10 wt%) and fly ash (5 wt%) particles are reinforced in AA336 aluminium alloy by stir casting process. Microstructure of samples are investigated and dry sliding wear factors viz., load (10 N–50 N), sliding distance (500 m–2500 m) and sliding velocity (1 ms−1–5 ms−1) are considered. Response surface methodology is used to design the experiments and wear weight loss of samples is measured. Regression equation is developed to predict the weight loss. Analysis of variance, significance test and confirmation test are used to find the significant wear parameters which affects the weight loss and the wear factors are optimized for obtaining lowest weight loss. Microstructure of samples showed uniform dispersion of particles in AA336 aluminium alloy. Wear test results showed that weight loss increased with increasing load and sliding distance. However, weight loss of samples decreased with increasing sliding velocity. Optimum dry sliding wear factors are found to be a load of 18.1 N, sliding distance of 905.4 m with a sliding velocity of 4.18 ms−1. [ABSTRACT FROM AUTHOR]

Abstract Existing ISO segmented and continuous separation methods for differentiating the two components contained within a bi-Gaussian stratified surface were developed based on the fit of the probability material ratio curve. In the present study, because of the significant effect of the plateau component on tribological behavior such as asperity contact, wear and friction, a truncated separation method is proposed based on the truncation of the upper Gaussian component defined by zero skewness. The three separation methods are applied to real worn surfaces. Surface-separation and surface-reconstruction results show that the truncated method accurately captures the upper component identically to the ISO and continuous ones. The identification of the lower component characteristics requires performing a curve fit procedure on the data left after truncation. However, the truncated method fails in identifying the upper component when the material ratio of the transition is less than 9%.

Fiber brushes with expanded graphite (EG) as a lubricant were successfully prepared. Compression properties of brushes filled with unbent fibers and bent fibers with different packing fractions were compared. Moreover, the friction and wear behaviors of the brushes with the same fiber packing fractions (17.5 vol%) but different EG volume contents were investigated. The effect of EG content on the tribological behavior of the fiber brush was analyzed according to the microstructure, debris, and worn surface of the brush and counterface disc. Results showed that both the elastic constant and compression strength of the brushes filled with bent fibers increased with an increase in packing fraction. Brushes filled with 17.5 vol% bent fibers had similar compression strength (2.69 MPa) but a lower elastic constant (150 N/mm) compared to the brush filled with 17.5 vol% unbent fibers (2.62 MPa and 425 N/mm). The friction coefficients and wear rates of the brushes decreased from 1.02 and 1.6 × 10−5 mm3/Nm to 0.25 and 0.28 × 10−5 mm3/Nm as the EG increased to a critical value (23.7 vol%). The worn surface and wear debris demonstrate that the wear mechanism of tin–bronze fiber brushes with EG sliding against brass discs transforms from adhesive wear to abrasive wear due to the formation of an EG lubricating film. [ABSTRACT FROM AUTHOR]

Abaca fibers show tremendous potential as reinforcing components in composite materials. The purpose of this study is to investigate the effect of abaca fiber content on physical, mechanical and tribological properties of abaca fiber reinforced friction composites. The friction composites were fabricated by a compression molder and investigated using a friction test machine. The experiment results show that surface treatment of abaca fibers could improve the mechanical properties of abaca fiber and interface bonding strength of the abaca fiber and composite matrix. Density of friction composites decreased with the increasing of abaca fiber content (0 wt%-4 wt%). The different content of abaca fibers had less effect on hardness of specimens, whereas large of impact strength. The specimen F3 with 3 wt% abaca fibers had the lowest wear rate and possessed the best wear resistance, followed by specimen F4 with 4 wt% abaca fibers. The worn surface morphologies were observed using the Scanning Electron Microscopy for study the tribological behavior and wear mechanism. The results show that a large amount of secondary contact plateaus presented on the worn surface of specimen F3 which had relatively smooth worn surface. [ABSTRACT FROM AUTHOR]

The characteristics of the worn surface of a pin were studied in the presence of a DC magnetic field. The experiments were conducted on a pin-on-disk tribometer in the ambient atmosphere. The medium carbon steel/medium carbon steel sliding couple was adopted. Compared to the pin formed in the absence of a magnetic field, oxidation becomes visible on the worn surface of the pin during the process of friction with the action of magnetic field. Fe2O3 was detected from the worn surface of a pin in the stable wear stage. The oxidation area of the worn surface of the pin gradually extends with increasing friction time. The wear of the pin decreases with extending of the oxidation area on the worn surface of the pin. The results reveal that the oxide layer formed on a pin worn surface is one of the key antiwear factors in the presence of a magnetic field. [ABSTRACT FROM AUTHOR]

The tribological performance of four different tribocomposite assemblies was comparatively investigated by sliding against a steel ring on a block-on-ring tribometer in a wide range of surface pressure (p) and sliding velocity (v), and the experimental results were described by a model. The results show that the friction coefficient in the stationary friction phase and the specific wear rate of the composite assemblies tend to follow the superior partner. Surprisingly, it is also found that the pv-load limit can be shifted to the higher pv-limit of the better partner. The results of the present work clearly show that the macroscopic combination of tribocomposites can be an excellent approach for the fabrication of tribological components, e.g. bearings, with long lifetime, high energy and eco-efficiency. [ABSTRACT FROM AUTHOR]

The piston skirt is one of the main contributors to the total mechanical loss in internal combustion engines. Usually, the skirt friction experiences a rapid change during the break-in period largely due to the wear of the machine marks or roughness against soft coatings. It is thus important to consider the effect of the change of the roughness for a realistic prediction of the piston skirt friction and system optimization. In this work, an existing model of piston skirt lubrication was improved with the consideration of a breaking in process for the most commonly used triangle machine marks. A new set of flow factors in the averaged Reynolds equation were analytically derived for the trapezoid shape formed after wear of the original triangle shape. A new asperity contact model was developed for the trapezoid shape. The calculation results reflect the trend of friction mean effective pressure (FMEP) during break-in in an engine test and showed quantitative agreement under the same amount of wear.

The current research focuses on dry sliding wear behaviour of end of life CRT panel glass and BN reinforced hybrid magnesium matrix composite fabricated through powder metallurgy route. CRT panel glass percentage (5, 10 & 15 wt %) and particle size (10, 30 & 50 μm) are varied to find its effect on wear performance and BN solid lubricant is added at a fixed level of 2%. Increase in reinforcement content and particle size decreases the wear rate whereas the opposite trend is found for coefficient of friction. ANOVA results reveal that all of the considered parameters significantly influence the response parameters. Taguchi based GRA is used for multi objective optimization and the worn surface SEM analysis is also performed. [ABSTRACT FROM AUTHOR]

The current study aimed to present the synthesis, characterization and wear behavior of AMMHCs at high temperature. This composite is reinforced with particles of B4C and MoS2 and are formed by stir casting route. Characterization of the hybrid composite is done by using Optical Microscope, SEM and XRD. The tests were conducted by means of pin on disc apparatus at a temperature 180°C for different sliding conditions like sliding speeds, sliding distances and applied loads. The results reveal that, the fairly homogeneous distribution of B4C and MoS2 particles are seen in Al matrix. XRD analysis has shown the major and minor phases present in prepared hybrid composites. Initially, specific wear rate is lower for lower sliding conditions and then enhances with increase in the sliding conditions. The addition of B4C and MoS2 particles decreases the specific wear rate of the Al2219 and AMMHCs. Worn surface of AMMHCs were examined to known the wear mechanism by using SEM. [ABSTRACT FROM AUTHOR]

The newly proposed continuous separation method for bi-Gaussian stratified surfaces, as the improvement of the existing ISO segmented one, is investigated. The continuous method provides an accurate surface-separation solution but is much more efficient. It has great stability to resist the fluctuations of the probability material ratio curves that are universally observed on real engineering surfaces. In contrast to the ISO segmented method, the continuous one is roughness-scale independent. When using a bi-Gaussian approach, it is difficult to identify component correlation lengths because of missing points in each individual component. An iterative process is used to overcome the defect in determining autocorrelation function (ACF). The ACF quality of the revised bi-Gaussian approach is better than that of the Johnson approach. [ABSTRACT FROM AUTHOR]

Fly ash particle reinforced aluminum matrix composite (AMCs) has been fabricated using a stir casting furnace by employing compocasting technique. The presence of fly ash particles in the compocast fabricated AMCs has been tested by X-ray diffraction and scanning electron microscopy (SEM). The wear behaviour of compocast fabricated AMCs and matrix alloy AA6061were tested using Pin-On-Disc apparatus. The effect of fly ash particulate content (0, 4, 8 and 12 wt.%) and temperature (40, 80, 120, 160, 200 and 240 °C) on wear rate and worn surface of the AMCs were studied. The reinforcement of hard fly ash particles is successful to improve the wear resistance of the compocast AMCs at all temperatures studied in this work. SEM micrograph of worm surface indicated that at elevated temperature the prime wear process for the AA6061 alloys were adhesion and metal flow, whereas for AA6061/Fly ash compocast composite adhesion, metal flow and oxidation are the most influencing wear process. [ABSTRACT FROM PUBLISHER]