Tribological Behavior Of Composites Research Articles

Tribological Behavior of Carbon Nanotube-Reinforced AZ91D Composites Processed by Cyclic Extrusion and Compression

Reciprocating wear tests were conducted to assess the wear resistance of CNT-reinforced AZ91D composites prepared by cyclic extrusion and compression (CEC). Effects of CEC, CNTs, and wear parameters on the tribological behavior of the composites were discussed. Results show that the matrix grain of the 0.5 wt% CNTs/AZ91D composites is largely refined from ~ 112 µm to 126.6 nm after eight passes of CEC. Accordingly, the hardness of the composites is increased by more than 82.0%. The wear rate of the CNTs/AZ91D composites decreases with the implement of CEC and the addition of CNTs. The lubrication effect of CNTs diminishes after CEC. Besides the reinforcing effect, the incorporated CNTs help to liberate the friction heat of the CNTs/AZ91D composites and reduce the welding of the wear debris due to their extraordinary thermal conductivity.

Effect of Ceramic and Metallic Reinforcement on Mechanical, Corrosion, and Tribological Behavior of Aluminum Composite by Adopting Design of Experiment Through Taguchi Technique

An attempt has been made to develop and study the properties and behavior of structure-based aluminum composite. Aluminum (AA6063)-based composites were fabricated by stir casting technique (also known as liquid metallurgy route) by varying weight percentage of metallic-based copper nitrate Cu (NO3)2 with fixed proposition of ceramic-based silicon nitride (Si3N4) reinforcement. The mechanical and corrosion properties and tribological behavior of composite were studied. Further, the sample microstructure and characterizations were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD) technique. The composite with fixed weight proportion of ceramic and higher metallic reinforced samples shows higher tensile strength, improved corrosion resistance, and higher hardness behavior. Due to higher hardness nature, the tribological properties of composite such as wear rate and coefficient of friction have been reduced. Moreover, the impact strength of composite decreased due to combination of ceramic and metallic reinforcement. In addition to the above study, design of experiment (DOE) was adopted to optimize the major wear test parameters such as percentage of reinforcement, applied load, sliding distance, and sliding speed. Finally, analysis of variance (ANOVA) was carried out to identify the most significant test parameter and its interaction affecting wear behavior and its coefficient of friction of composite sample.

Analysis of wear properties of Zn-based composites using the Taguchi method

Abstract The tribological behavior of composites based on zinc aluminum ZA27 alloy, reinforced with silicon carbide (SiC) and graphite (Gr) particles is analyzed using the Taguchi method and described in this paper. Two sample composites were tested: the first containing 10 % of SiC and the second containing 10 % of SiC and 3 % Gr particles. They were prepared by the compo-casting procedure. The experiments were carried out using a block-on-disc tribometer under dry sliding test conditions. The tests were conducted with sliding speeds of 0.25, 0.5 and 1.0 m×s−1, normal loads of 10, 20 and 30 N and a sliding distance of 300 m. The wear surface of the composite material was examined using scanning electronic microscopy (SEM) and energy dispersive spectrometry (EDS). The influence of various parameters on the wear behavior was investigated by means and analysis of variance (ANOVA).

Effect of SiC and Al2O3 particles addition to AA 2900 and AA 2024 MMC’s synthesized through microwave sintering

Aluminum alloy AA-SiC and AA-Al2O3 composites with 3, 6 & 9 weight% of SiC and Al2O3 with average of 10 µm particle size are fabricated through powder metallurgy. The density, Rockwell hardness, Compressive strength and tribological behavior of composites were found to be improved. AA 2024 with 6% Al2O3 reinforced MMC’s samples were exhibiting improved hardness results, strength behavior and stress-strain behavior when the samples are microwave sintered. AA 2900 with 6 wt% Al2O3 exhibited good ductility and formability properties closer to AA 2024. AA 2900 with 6 wt% Al2O3 displayed better frictional coefficient behavior compared to AA 2024.

Role of Metallic Nanofillers on Mechanical and Tribological Behaviour of Carbon Fabric Reinforced Epoxy Composites

In this study, hybrid composites based on carbon fabric and epoxy (C/Ep) were fabricated by hand lay-up method followed by compression moulding. The C/Ep with optimum carbon fiber (60 wt%) was chosen as a reference material, and to it, the metallic nanoparticles like aluminum (Al) and zinc (Zn) of different wt% (0.5 and 1.0) were included as secondary fillers. To understand the synergism effect of these hybrid reinforcements, mechanical properties and tribological behavior of composites were studied. From the test results, it was proved that hybridization improved the mechanical and tribological properties. The C/Ep consisting of 0.5 wt% Zn and Al showed higher tensile properties in comparison with all other fabricated composites. Increase in flexural strength and flexural modulus also observed as the filler content increased in C/Ep composite. Higher impact strength is noted at 1 wt% Zn filled C/Ep composite. Wear test data revealed that 0.5 wt% Zn in C/Ep has got superior wear resistance. Wear mechanisms were discussed using scanning electron micrographs of selected worn surfaces of the composites.

Si3N4/graphene nanocomposites for tribological application in aqueous environments prepared by attritor milling and hot pressing

Advanced ceramic materials have proved their superior wear resistance as well as mechanical and chemical properties in a wide range of industrial applications. Today there are standard materials for components and tools that are exposed to severe tribological, thermal or corrosive conditions. The main aim of this work is to develop novel, highly efficient tribological systems on the basis of ceramic/graphene nanocomposites as well as to prove their superior quality and to demonstrate their suitability for technical applications e.g. for slide bearings and face seals in aqueous media. Current research in the field of ceramic nanocomposites shows that is possible to make ceramic materials with improved mechanical and tribological properties by incorporating graphene into the Si3N4 structure. Multilayered graphene (MLG) was prepared by attritor milling at 10h intensive milling of few micrometer sized graphite powders. The large quantity, very cheap and quick preparation process are a main strengths of our MLG. Si3N4/MLG nanocomposites were prepared by attritor milling and sintered by hot pressing (HP). The Si3N4 ceramics were produced with 1wt%, 3wt%, 5wt% and 10wt% content of MLG. Their structure was examined by transmission electron microscopy (TEM). The tribological behavior of composites in aqueous environment was investigated and showed the decreasing character of wear at increased MLG content. This new approach is very promising, since ceramic microstructures can be designed with high toughness and provide improved wear resistance at low friction.

Surface characterization and specific wear rate prediction of r-GO/AZ31 composite under dry sliding wear condition

The effect of reduced graphene oxide (r-GO) nanosheets on the dry sliding wear behaviour of AZ31 alloy composites produced by solvent based powder metallurgy technique has been investigated. The percentage of reinforcement addition was limited to 0.2% and 0.4%. Results show that r-GO nano-sheets considerably increases the microhardness upto 64.4 HV. The tribological behaviour of composites was investigated by pin on disc tribometer for an optimal set of control factors. Reinforcement weight percentage, load, sliding distance and sliding velocity was taken as input parameters. Taguchi coupled artificial neural network has been used to plan and analyze the experiment. Based on the study it was observed that reinforcement weight percentage and load are the most influencing factor which affects the specific wear rate. Adapted ANN results show better predictablity with R-value 99.98% and the same was effectively used to investigate the behaviour of each control factors.

Wear Analysis of Nano ZrC Reinforced with Cu - Cr using Response Surface Methodology

In the present study the influence of nanoZrC particles on the dry sliding wear behavior of Cu - Cr alloy composites produced by powder metallurgy method has been explored. The reinforcement percentage was varied from 0 wt. % to 8 wt. %. The consequences indicated that with the accumulation of nanoZrC particles into the matrix reduce the wear loss correspondingly. The tribologicalbehavior of composites was studied by SEM and pin on disc apparatus. Reinforcement wt. %, load and sliding distance were taken as the process parameters. Response surface methodology has been used to plan and analyze the experiment. Consequences indicated that the sliding distance and load are the most influencing parameter on wear loss of composites.

Optimization on Wear Behavior of Al-12Si Alloy Reinforced with ZrC Nano Particle using Factorial Design

This paper evaluates the specific wear rate and friction coefficient of ZrCnano particle reinforced with Al-12Si metal matrix composites produced by powder metallurgy. The reinforcement percentage was 5 wt. % and 10 wt. %. The result showed that with the increase of ZrCnano particles into the matrix decrease the specific wear rate respectively. The result also showed that with the increase of ZrCnano particles into the matrix decrease the friction coefficient. The tribologicalbehavior of composites was studied by SEM and pin on disc apparatus. As input parameters such as reinforcement, load and sliding distance were modeled by applying general 23 factorial designs. As response parameter, specific wear rate was obtained experimentally by a set of pin-on-disc tests. Screening design is employed for evaluation of interactions between response parameter and input parameters. The specific wear rate showed various results depending on the initial values of parameters. The results showed that all parameters had significant effects on the specific wear rate and friction coefficient at 95% confidence level.

Dry sliding wear investigation of Al6082/Gr metal matrix composites by response surface methodology

The effect of graphite particles on the dry sliding wear behaviour of Al6082 alloy composites produced by conventional stir casting method has been investigated. The percentage of reinforcement was varied from 0% to 12% in a step of 3. The result showed that with the addition of graphite particles micro- and macro-hardness reduced by 11.11% and 10.44%, respectively. The tribological behaviour of composites was investigated by pin on disc apparatus. Percentage reinforcement, load, sliding speed and sliding distance were taken as the process variable. Response surface methodology has been used to plan and analyze the experiment. Results showed that sliding distance is the most influential factor and load is the factor which affects the wear least.

Characterization, pore size measurement and wear model of a sintered Cu–W nano composite using radial basis functional neural network

Cu–(5–20%) W composite preforms, with a density of 94% were prepared through mechanical milling, mixing, compaction, sintering and hot extrusion. The X-ray Diffraction analysis, Particle Size analysis, Transmission Electron Microscope, Scanning Electron Microscope and Energy Dispersive Spectrum were used for the characterization studies. The pore size during different sintering atmospheres and the pore size reduction during extrusion, were studied through Auto CAD 2010 software. The wear experiments were conducted using the pin-on-disc wear tester. The various regions in the wear mechanisms were identified through the wear distribution map. The Radial Basis Functional Neural Network has been used in an attempt to predict the mechanical and tribological behavior of composites, and useful conclusions have been made.

A comparative analysis of woven jute/glass hybrid polymer composite with and without reinforcing of fly ash particles

The objective of this research article is to compare the mechanical and tribological properties of jute‐glass‐fiber‐reinforced epoxy (J‐G‐E) hybrid composites with and without fly ash particulate filler. A dry hand lay‐up technique is used to fabricate all the laminates. The properties including flexural strength, tensile strength, flexural modulus, and erosion behavior of all the composites are evaluated as per American Society for Testing and Materials (ASTM) standards. The fly ash particulate‐filled hybrid composite shows a better mechanical and tribological property. The maximum flexural strength and flexural modulus are obtained for GJGJ+ 5 wt% fly ash filler epoxy composites. Whereas the maximum tensile strength is obtained for GJJG+ 10 wt% fly ash filler epoxy composites. Scanning Electron Microscopy (SEM) analysis also has been carried out to categorize mechanical and tribological behavior of composites. POLYM. COMPOS. 37:658–665, 2016. © 2014 Society of Plastics Engineers

Characterisation of the friction and wear behaviour of textile reinforced polymer composites in contact with diamond-like carbon layers

The tribological behaviour of composites, particularly in contact with steel, is to be estimated as relatively weak. As a promising improvement, the application of modern coatings is considered. In this context, the results of frictional and wear investigations of carbon fibre reinforced epoxy and polyethersulfone as well as glass fibre reinforced polypropylene composites in contact with coated and uncoated steel 100Cr6 are presented. The coating consists of diamond-like carbon (ta-C) layer. A remarkable outcome of the study is the substantial decrease of the specific wear rate of the investigated material pairings by the application of carbon coated metal. The tribological system, which is responsible for the excellent tribological characteristics, is determined by predominantly sliding wear and suppressed abrasive wear.

New Aluminum Foam/Polyformaldehyde Interpenetrating Phase Composites Prepared by Injection Molding

A new type of interpenetrating phase composite was formed by filling 70%-porous open-cell aluminum foam with polyformaldehyde through injection molding process. The results showed that both mechanical properties and tribological behavior of composites were improved. The interphase behaviour of aluminum foam/polyformaldehyde composites was examined by scanning electron microscopy(SEM).The worn surfaces of composites were also examined and discussed. It could be indicated that injection molding and Al foam surface preprocessing including both alkaline wash and KH550 treatment for Al foam/ POM composites was available. The new composite could be used where moderate strength and wear properties are needed.

UV or AO Irradiation Effects on the Tribological Properties of the Talc/GF/PI Composites

The development of polyimide (PI) composites, particularly for use in aerospace and tribological applications, has gained importance over the past decades. However, there have been scarce studies on the ultraviolet (UV) or atomic oxygen (AO) irradiation characteristics of the polyimide composites, the understanding of which may aid in expanding its application in space environment. To study the irradiated effects of UV and AO on the tribological behaviour of the PI composites, glass fibers (GF)-reinforced PI composites filled with Talc were irradiated by UV or AO in a ground based simulation system. Glass fibers (GF) reinforced PI composites filled with talc were fabricated by means of a hot press molding technique. The volume contents of the talc (10, 20, 30 %) were chosen to study the effects of filler content on the tribological behavior of the composites, while the proportion of the glass fiber was kept at 15 vol %. To contrast the different effects of UV and AO irradiation on the tribological properties of the composites, experiments without irradiation and after UV or AO irradiation were conducted. The specimens of the composites were irradiated with UV for a period of 4h, while AO irradiation chosen for 6h. Dynamic mechanical analysis (DMA) and thermal gravimetric analysis (TGA) measurements were conducted. The friction and wear behaviors of the composites, rotating against GCr15 steel balls, were investigated on a ball-on-disk test rig. at room temperature and at a rotating speed of 0.1256 m/s and a load of 1N. Experimental results revealed that the composites exhibited high modulus and wear rate values with increasing talc content, but low coefficients of friction (COF). After AO irradiation, the COF of the composites increased, but UV irradiation had no obvious effect on the tribological property of the composites. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) study of the composite surface showed that the chemical composition of the surface changed after UV irradiation because of the photooxidation and rough surface or even mountain-like structures were formed after AO erosion. The experiments indicated that the different space environments had an important effect on the tribological properties of the polymer composites. It is expected that this study may help expand the application of the polyimide composites in the field of space.

In State of Art: Mechanical and tribological behaviour of polymeric composites based on natural fibres

In this article, a comprehensive literature review on the mechanical and tribological behaviour of polymeric composites based on natural fibres is introduced. The effects of volume fraction, orientations, treatments and physical characteristics of different types of natural fibres on the mechanical and tribological properties of several thermoset and thermoplastic polymers are addressed. The effects of the tribological operating parameters (applied load, sliding velocity and sliding distance) on the frictional and wear performance of natural fibre polymer composites are demonstrated. The collected date and analyses revealed that volume fraction, orientations, type of treatment and physical characteristics of the natural fibres significantly influence the mechanical and tribological behaviour of composites. The most influence key in designing natural fibre/polymer composite is the interfacial adhesion of the fibre with the matrix. NaOH chemical treatment found to be the most useful treatment method to enhance the interfacial adhesion of the natural fibres with the matrix, while other techniques exhibited either no effect or deterioration on the fibre strength. Frictional characteristics of the natural fibre composites are poor and solid lubricants are recommended to reduce the friction coefficient of the materials.

Tribological behavior of CNTs-Cu and graphite-Cu composites with electric current

CNTs-Cu and graphite-Cu composites were separately prepared by powder metallurgy technique under the same consolidation processing. Tribological behavior of the composites with electric current was investigated by using a pin-on-disk friction and wear tester. The results show that the friction coefficient and wear rate of the composites decrease with increasing the reinforcement content, and increase with increasing the electric current density; the effects of electric current are more obvious on tribological properties of graphite-Cu composites than on CNTs-Cu composites; for graphite-Cu composites the dominant wear mechanisms are electric arc erosion and adhesive wear, while for CNTs-Cu composites are adhesive wear.

Tribological behavior of polyetheretherketone composites containing short carbon fibers and potassium titanate whiskers in dry sliding against steel

AbstractPolyetheretherketone (PEEK) composites reinforced by short carbon fibers (SCF) and potassium titanate whiskers (PTW) were prepared using twin‐screw extrusion compounding and injection molding. The tribological properties of hybrid composites were investigated in dry sliding condition against steel. The effects of filler contents on the wear behavior were studied. It was found that the hybrid composite showed an excellent tribological property in dry sliding condition. Applied load had great effect on the tribological behavior of the composites. In most cases, the friction coefficient of the composite decreased with the load rising. The composites with higher CF contents showed outstanding tribological performances at low load but could worsen the wear behavior at high load. Because of the positive effect of PTW, high PTW loading composites presented low wear rate at low load. At high loads, the composites with lower PTW contents had better wear resistance. The scanning electron microscopy (SEM) observation revealed that abrasion wear was attributed to the lower wear resistance of the high PTW content composite at high load. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Effect of addition of graphite particulates on the wear behaviour in aluminium–silicon carbide–graphite composites

Aluminium matrix composites with multiple reinforcements (hybrid AMCs) are finding increased applications because of improved mechanical and tribological properties and hence are better substitutes for single reinforced composites. Few investigations have been reported on the tribological behaviour of these composites with % reinforcement above 10%. The present study focuses on the influence of addition of graphite (Gr) particulates as a second reinforcement on the tribological behaviour of aluminium matrix composites reinforced with silicon carbide (SiC) particulates. Dry sliding wear tests have been performed to study the influence of Gr particulates, load, sliding speed and sliding distance on the wear of hybrid composite specimens with combined % reinforcement of 2.5%, 5%, 7.5% and 10% with equal weight % of SiC and Gr particulates. Experiments are also conducted on composites with % reinforcement of SiC similar to hybrid composites for the sake of comparison. Parametric studies based on design of experiments (DOE) techniques indicate that the wear of hybrid composites decreases from 0.0234 g to 0.0221 g as the % reinforcement increases from 3% to 7.5%. But the wear has a tendency to increase beyond % reinforcement of 7.5% as its value is 0.0225 g at.% reinforcement of 10%. This trend is absent in case of composites reinforced with SiC alone. The values of wear of these composites are 0.0323 g, 0.0252 g and 0.0223 g, respectively, at.% reinforcement of 3%, 7.5% and 10% clearly indicating that hybrid composites exhibit better wear characteristics compared to composites reinforced with SiC alone. Load and sliding distance show a positive influence on wear implying increase of wear with increase of either load or sliding distance or both. Whereas speed shows a negative influence on wear indicating decrease of wear with increase of speed. Interactions among load, sliding speed and sliding distance are noticed in hybrid composites and this may be attributed to the addition of Gr particulates. Such interactions are not present in composite reinforced with SiC alone. Mathematical models are formulated to predict the wear of the composites.

Tribological properties of nickel-based self-lubricating composite at elevated temperature and counterface material selection

Solid lubricating materials are necessary for development of new generation gas turbine engines. Nickel-based self-lubricating composites with graphite and molybdenum disulfide as lubricant were prepared by powder metallurgy (P/M) method. Their tribological properties were tested by a MG-2000 high-temperature tribometer from room temperature to 600 °C. The structure of the composite was analyzed by XRD and worn surface morphologies were observed by optical microscope. The effects of counterface materials on tribological behavior of composites were investigated. It was found that chromium sulfide and tungsten carbide were formed in the composite by adding molybdenum disulfide and graphite, which were responsible for low-friction and high wear-resistance at elevated temperatures, respectively. The average friction coefficients (0.14–0.27) and wear rates (1.0–3.5 × 10 −6 mm 3/(N m)) were obtained for Ni–Cr–W–Fe–C–MoS 2 composite when rubbed against silicon nitride from room temperature to 600 °C due to a synergetic lubricating action of graphite and molybdenum disulfide. The optimum combination of Ni–Cr–W–Fe–C–MoS 2/Ni–Cr–W–Al–Ti–C showed lower friction than other counter pairs. The graphite played the main role of lubrication at room temperature, while sulfides were responsible for low friction at high temperature.