Study of Non-lubricated Wear of the Al–Si Alloy Composite Reinforced with Different Ratios of Coarse and Fine Size Zircon Sand Particles at Different Ambient Temperatures

In the present work, a detailed study of ceramic reinforcement of different size ranges in the matrix of LM13 alloy on the friction and wear behavior has been carried out. For this purpose, LM13/Zr composite containing 10 wt% zircon sand particles of different size ranges using stir casting process has been developed. Zircon sand particles were incorporated in two ways: firstly as single size reinforcement and secondly dual size reinforcement. Durability of the composites was tested by finding the wear rate of the composite against the steel disk by pin-on-disk method. Addition of zircon sand particles in the LM13 alloy improves the hardness of the composite as well as wear resistance. Wear rate of the developed composites was tested under different test conditions by varying the applied load and ambient temperatures. Wear rate of the composite changes significantly at different ambient temperatures. SEM analysis of the worn surfaces was done to know the operative wear mechanism.     

Desirability based multiobjective optimisation of abrasive wear and frictional behaviour of aluminium (Al/3.25Cu/8.5Si)/fly ash composites

Aluminium alloy (Al/3.25Cu/8.5Si) composites reinforced with fly ash particles of three different size ranges (53–75?μm, 75–103?μm and 103–125?μm) in 3, 6 and 9 wt-% were fabricated using liquid metallurgy technique. Pin on disc abrasive wear tests were carried against the disc surface fixed with SiC emery paper (120 grades). A mathematical model was developed to predict the abrasive wear and coefficient of friction of the composites. Analysis of variance technique was used to check the validity of the developed model. Composites reinforced with coarse fly ash particles exhibited better abrasive wear resistance than those reinforced with fine fly ash particles. Abrasive wear in composites with fine fly ash particles is a combination of adhesive wear and abrasive wear. Larger fly ash particles present in composites gets fractured into fine particles and entrapped between the composite pin and the disc, thereby decreasing the wear rate. Worn surfaces of the pins were then analysed using scanning electron microscopy to study the wear mechanisms of the composites. The abrasive wear was optimised using desirability based multiobjective optimisation technique.     

Effect of Particle Size on Tribological Behavior of Rice Husk Ash–Reinforced Aluminum Alloy (AlSi10Mg) Matrix Composites

Rice husk ash of three different particle size ranges (50–75, 75–100 and 100–150 μm) a 3, 6, 9, and 12% by weight is reinforced with an aluminum alloy (AlSi10Mg) using the liquid metallurgy method. The dry sliding wear behavior of the composites in the cast conditions is examined using the pin-on-disc tribotesting machine for three different loads (20, 30, and 40 N) with three different sliding velocities (2, 3, and 4 m/s). The results reveal that the composite reinforced with the coarse rice husk ash particles exhibits superior wear resistance compared to the fine rice husk ash particles. The wear rate of the composite decreased with an increase in the weight percentage of rice husk ash particles for all size ranges. Finally, the wear mechanism was investigated with the worn surface using a scanning electron microscope.     

Impact wear resistance of WC/Hadfield steel composite and its interfacial characteristics

A composite coating of WC/Hadfield steel was fabricated through centrifugal casting process to improve the impact wear resistance of Hadfield steel under the conditions of low or medium impact energy. The interfacial structure between WC ceramic particle and the steel matrix was analyzed with scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The impact wear tests at different impact energy were carried out on a MLD-10 type impact wear rig to investigate the wear-resistant properties of three kinds of composites with different WC particle sizes. For comparison, the wear tests of Hadfield steel were also carried out under the same conditions. The results show that WC particles are partially dissolved in the steel during centrifugal casting. The elements W, C and Fe in steel react to form new carbides such as Fe₃W₃C or M₂₃C₆, which precipitate around former WC particles forming fine particles during subsequent solidification. So the interface between WC particles and Hadfield steel matrix is a strong metallurgical bonding. The composite reinforced with smaller WC particles has better impact wear resistance than that of Hadfield steel regardless of impact energy level. Whereas, the composite reinforced with larger WC particles has better impact wear resistance property than that of Hadfield steel when the impact energy is small but an opposite result is gained when the impact energy is higher. So, it is very essential to choose suitable size of WC particles as reinforcement in Hadfield steel to make the composite material more durable in the service conditions.     

Dry sliding wear of fly ash particle reinforced A356 Al composites

In the present study aluminium alloy (A356) composites containing 6 and 12 vol. % of fly ash particles have been fabricated. The dry sliding wear behaviour of unreinforced alloy and composites are studied using Pin-On-Disc machine at a load of 10, 20, 50, 65 and 80 N at a constant sliding velocity of 1 m/s. Results show that the dry sliding wear resistance of Al-fly ash composite is almost similar to that of Al₂O₃ and SiC reinforced Al-alloy. Composites exhibit better wear resistance compared to unreinforced alloy up to a load of 80 N. Fly ash particle size and its volume fraction significantly affect the wear and friction properties of composites. Microscopic examination of the worn surfaces, subsurfaces and debris has been done. At high loads (>50 N), where fly ash particles act as load bearing constituents, the wear resistance of A356 Al alloy reinforced with narrow size range (53–106 μm) fly ash particles were superior to that of the composite having the same volume fraction of particles in the wide size range (0.5–400 μm).     

Effect of particle size on tribological behavior of Ni3Al matrix high temperature self-lubricating composites

The Ni₃Al matrix high temperature self-lubricating composites with different particle size were fabricated by the powder metallurgy technique. The effect of particle size on the mechanical and tribological properties of the composites was investigated in this paper. The results showed that the coarse particle composite exhibited the lowest friction coefficient and wear rate compared to the fine particle ones at a wide temperature range from room temperature to 1000 °C. The reason for the low wear rate was that the coarse bulk phase could provide better deformation resistance and higher load bearing capacity than the fine microstructure.     

Effect of particle size on tribological behavior of Ni3Al matrix high temperature self-lubricating composites

The Ni₃Al matrix high temperature self-lubricating composites with different particle size were fabricated by the powder metallurgy technique. The effect of particle size on the mechanical and tribological properties of the composites was investigated in this paper. The results showed that the coarse particle composite exhibited the lowest friction coefficient and wear rate compared to the fine particle ones at a wide temperature range from room temperature to 1000 °C. The reason for the low wear rate was that the coarse bulk phase could provide better deformation resistance and higher load bearing capacity than the fine microstructure.     

High stress abrasive wear behaviour of aluminium hard particle composites: Effect of experimental parameters, particle size and volume fraction

High stress abrasive wear behaviour of aluminium alloy (ADC-12)–SiC particle reinforced composites has been studied as a function of applied load, reinforcement size and volume fraction, and has been compared with that of the matrix alloy. Two different size ranges (25–50 and 50–80 μm) of SiC particles have been used for synthesizing ADC-12–SiC composite. The volume fraction of SiC particles has been varied in the ranges from 5 to 15 wt%. It has been noted that the abrasive wear rate of the alloy reduced considerably due to addition of SiC particle and the wear rate of composite decreases linearly with increase in SiC content. It has also been noted that the wear resistance of composite varies inversely with square of the reinforcement size. The wear rate of the alloy and composite has been found to be a linear function of applied load but invariant to the abrasive size; at critical abrasive size, transition in wear behaviour is noted. This has been explained through analytically derived equations and wear–surface examination.     

Abrasive wear behaviour of B4C particle reinforced Al2024 MMCs

In this study, the effects of volume fraction and particle size of boron carbide on the abrasive wear properties of B₄C particle reinforced aluminium alloy composites have been studied. For this purpose, a block-on-disc abrasion test apparatus was utilized where the samples slid against the abrasive suspension mixture at room conditions. The volume loss, specific wear rate and roughness of the samples have been evaluated. The effects of sliding time, particle content and particle size of B₄C particles on the abrasive wear properties of the composites have been investigated. The dominant wear mechanisms were identified using scanning electron microscopy. The results showed that the specific wear rate of composites decreased with increasing particle volume fraction. Furthermore, the specific wear rate decreased with increasing the size of particle for the composites containing the same amount of B₄C. Hence, it is deduced that aluminium alloy composites reinforced with larger B₄C particles are more effective against the abrasive suspension mixture than those reinforced with smaller B₄C particles.     

Morphology and Toughness of Abrasive Particles and Their Effects on the Friction and Wear of Friction Materials: A Case Study with Zircon and Quartz

This study examined the friction and wear of brake friction materials containing two different abrasives: zircon and quartz. Commercial grade abrasives with two different sizes (fine and coarse) were compared in terms of the effects of the size, shape, and toughness of the abrasive particles on the friction and wear of the friction material and counter discs. The results showed that the morphology of the abrasives has a considerable effect on the friction effectiveness and wear of the friction couple. The level of friction was higher in the case of using quartz than zircon, and smaller particles were more effective in increasing the coefficient of friction. The toughness of the abrasives also played important roles in determining the friction effectiveness. Improved heat resistance at elevated temperatures was achieved when coarse zircon was used. The wear of the friction material was also dependent on the morphology and toughness of the abrasives and the large abrasive particles produced more wear on the gray iron disc.     

Abrasive wear of cast aluminium alloy-zircon particle composites

The abrasive wear rates of particulate composites of an Al-11.8Si-4Mg alloy containing up to 0.35 volume fraction of zircon particles (average size, 100 μm) were measured on an 80 grit aloxide cloth sheet as a function of the volume fraction of zircon, the applied load and the number of passes over the abrasive paper. When the volume fraction of zircon is above a critical value of 0.09, the abrasive wear resistance (reciprocal of the wear rate) increases with the volume fraction of zircon according to the rule of mixtures. When the volume fraction is fixed, the abrasive wear resistance increases with the number of passes possibly because of blunting of the alumina particles of the abrasive cloth. No improvement in the abrasive wear resistance of composites over the matrix alloy was observed when the volume fraction of zircon was below 0.09. Scanning electron microscopy studies of the abraded surfaces of composites revealed fractured zircon particles but no evidence of filler particle pull-outs or debonding at the interface was obtained.     

Dry Sliding Wear Behavior of Palmyra Shell Ash–Reinforced Aluminum Matrix (AlSi10Mg) Composites

High strength, light weight, ease of fabrication, excellent castability, and good wear resistance make aluminum alloy composites suitable for commercial applications. In this work, a silica-rich ash particle (palmyra shell ash) was reinforced with aluminum alloy (AlSi10Mg) composites and its mechanical and tribological properties were studied. The aluminum alloy was reinforced with 3, 6, and 9 wt% of palmyra shell ash particles, and its dry sliding wear behavior was studied using a pin-on-disc machine under different loading conditions. The result shows that the dry sliding wear resistance of Al–palmyra shell ash composites was almost similar to that of fly ash– and rice husk ash–reinforced Al-alloy composites and these composites exhibit better wear resistance compared to unreinforced alloy. The palmyra shell ash particle weight fraction significantly affects the wear and friction properties of the composites. Scanning electron microscopic examination of the worn surface reveals that at various loads palmyra shell ash particles act as load-bearing constituents and the wear resistance of the reinforced palmyra shell ash with a size range of 1–50 µm was superior to that of unreinforced alloy. Mechanical properties (hardness and tensile strength) were also studied and it was observed that the reinforced Al-alloy showed a significant increase in mechanical properties.     

纳米碳化硅增强铜基复合材料的组织及其磨损性能

为了探求在常温下制备颗粒弥散增强金属基复合材料的方法，采用复合电铸工艺在室温下制备了纳米碳化硅粒子弥散增强铜基复合材料，对其表面形貌、微观组织结构进行了观察，对显微硬度、磨损性能及导电性能进行了测试。结果表明：纳米碳化硅粒子均匀弥散分布在铜基体中，且与基体结合良好；复合材料表面平整、细密；与电沉积纯铜材料相比，其显微硬度明显提高，磨损性能改善，导电性能下降幅度不大。     

Wear Behavior of Magnesium Alloy AZ91 Hybrid Composite Materials

The influence of hybrid reinforcements including silicon carbide and graphite particles with a size 37–50 μm on the wear characteristics of AZ91 magnesium alloy was studied. The dry sliding wear test was conducted using a pin-on-disc wear testing machine in the load range of 20 to 80 N at different sliding velocities in the range of 1.047 to 2.618 m/s. The results show that the wear resistance of composites was much better than that of the base matrix material under the test conditions. At a speed of 1.047 m/s and load of 40 N, the wear rate (mm³/km) of the unreinforced alloy was 6.3, which reduced to 3.8 in the case of 3% reinforced composite. The antiwear ability of magnesium alloy composite was found to improve substantially with the increase in silicon carbide and graphite content from 1 to 3% by weight and the wear rate was found to decrease considerably. At a speed of 1.047 m/s and load of 80 N, the wear rate (mm³/km) reduced from 11.8 to 9.1 when the reinforcement content increased from 1 to 3%. However in both the unreinforced alloy and reinforced composite, the wear rate increased with the increase in load and sliding velocity. An increase in the applied load increases the wear severity by changing the wear mechanism from abrasion to particle cracking-induced delamination. The worn surface morphologies of the composite containing 3% reinforcement by weight for the sliding velocity of 1.047 m/s were examined using scanning electron microscopy. Different wear mechanisms, namely, abrasion, oxidation, and delamination, have been observed.     

高导电耐磨铜基复合材料的研究

用冷压-烧结-热挤压工艺制备了SiCp／Cu复合材料，得到组织均匀、致密、导电导热的复合材料。干磨损试验结果表明，随着SiC含量的提高，复合材料具有更高的耐磨性；SiC颗粒增强物的加入减小了材料的粘着磨损，使复合材料在高载荷条件下具有更为优越的耐磨性。SiC体积分数不超过15％的铜基复合材料具有比铬锆铜合金更高的导电、导热性能和耐磨性。     

Effects of Ceramic Fiber on the Friction Performance of Automotive Brake Lining Materials

Friction material containing aluminum-silicon fiber was prepared. The effects of the aluminum-silicon fiber content on fade, recovery, and wear properties of the friction material were studied using a friction tester with a constant speed. Morphologies of the wear surfaces were observed by scanning electron microscopy (SEM). It was found that the heat fading resistance property of friction material was clearly improved when the content of aluminum-silicon wool was more than 5 wt.%, but the property of recovery declined and the wear rate increased slightly at the same time. The wear mechanisms were adhesive and abrasive, caused by the zircon sand, for the semi-metal friction material, while the abrasive wear of hybrid fiber reinforced composites was caused by cracked ceramic fibers and zircon sand.     

Solid particle erosion studies on biomorphic Si/SiC ceramic composites

Solid particle erosion tests were conducted on four different types of silicon carbide ceramic composites. The composites are cotton fabric based Si/SiC with and without chemical vapour infiltration, fine teak wood powder based Si/SiC and coarse teak wood powder based Si/SiC. The erodents used are angular SiC particles of average size 80, 250 and 450 μm. The velocities with which particles impacted on the target materials were varied from 20 to 50 m/s. Similarly the angle of impact was varied from 20° to 90°. Scanning electron microscopic observations on the eroded surface show brittle and cleavage like fracture. Fine teak wood powder based Si/SiC ceramic shows better erosion resistance than the other ceramics. Homogenous distribution of SiC grains with the presence of very fine grains of silicon and carbon is responsible for the improved erosion resistance. The higher erosion rate in cotton fabric based SiC arises from its microstructure. Here, the free carbon and free silicon grains are large in size and the SiC phase has very low hardness as compared to the erodent.     

Effect of SiC Particle Size on Wear Properties of Al2O3·SiO2/SiC/Mg Hybrid Metal Matrix Composites

The aim of this study was to investigate the effect of SiC particle size on the wear properties of magnesium-based hybrid metal matrix composites (MMCs) reinforced with Saffil short fibers and SiC particles. Hybrid MMCs with different SiC particle sizes of 1, 7, and 20 μm, respectively, were fabricated by the squeeze infiltration process. The volume fractions of Saffil short fibers and SiC particles in the hybrid composites were 15 and 5%, respectively. Wear tests were carried out using a ball-on-disk against a steel ball under the dry sliding condition. The test results showed that the composite with large-sized SiC particles had an improved wear resistance compared with the smaller sized particles.     

Tribological Behavior of Micrometer- and Submicrometer-Size Cenosphere Particulate-Filled Glass Fiber–Reinforced Vinylester Composites Under Dry and Water-Lubricated Sliding Conditions

In this work, the tribological behavior of micrometer and submicrometer cenosphere particulate–filled E-glass fiber–reinforced vinylester composites have been investigated on a pin-on-disc tester under dry sliding and water-lubricated sliding conditions. Three different uniform sizes of cenosphere particles (2 μm, 900 nm, 400 nm) were used as fillers in the glass fiber–reinforced vinylester composites. The weight fraction of cenosphere particles has been varied in the ranges from 5, 10, 15, to 20 wt%. The experimental results show that all of the composites exhibited lower coefficient of friction and lower wear resistance under water-lubricated sliding conditions than under dry sliding. It has been noted that the submicrometer size (400 nm) cenosphere particulates as fillers contributed significantly to improve the wear resistance. It has also been noted that 10 wt% of the cenosphere particles is the most effective in reducing the wear rate and coefficient of friction. Effects of various wear parameters such as applied normal loads, sliding speeds, particle size, and particle content on the tribological behavior were also discussed. In order to understand the wear mechanism, the morphologies of the worn surface were analyzed by means of scanning electron microscopy (SEM) for composite specimens under both dry and water-lubricated sliding conditions.     

Tribological behavior of microwave processed copper–nanographite composites

Excellent properties offered by nanographite particles are exploited as a reinforcement to the copper matrix. The effects of graphite particle size, spatial distribution, normal load and sliding speed on the friction and wear performance of microwave sintered copper metal matrix composites were studied using a pin-on-disc tribometer. Copper–nanographite composites show higher wear resistance and low coefficient of friction compared to copper–graphite composites. High surface area of nanographite particles embedded in copper matrix exhibited high adherent graphite tribo-layer at the contact surface. Formed graphite layer reduces the sub-surface deformation of the composite by way of reduced frictional force.