Tribological properties of metal matrix-graphite particle composites (original) (raw)
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Tribology of Metal Matrix Composites
Metal matrix composites (MMCs) are an important class of engineering materials that are increasingly replacing a number of conventional materials in the automotive, aerospace, marine, and sports industries due to their lightweight and superior mechanical properties. In MMCs, nonmetallic materials are embedded into the metals or the alloys as reinforcements to obtain a novel material with attractive engineering properties, such as improved ultimate tensile strength, ductility, toughness, and tribological behavior. In this chapter, an attempt has been made to summarize the tribological performance of various MMCs as a function of several relevant parameters. These parameters include material parameters (size, shape, volume fraction, and type of the reinforcements), mechanical parameters (normal load and sliding speed), and physical parameters (temperature and the environment). In general, it was shown that the wear resistance and friction coefficient of MMCs are improved by increasing the volume fraction of the reinforcements. As the normal load and sliding speed increase, the wear rate of the composites increases and the friction coefficient of the composites decreases. The wear rate and friction coefficient decrease with increasing temperature up to a critical temperature, and thereafter both wear rate and friction coefficient increase with increasing temperature. The nano-composites showed best friction and wear performance when compared to micro-composites.
TRIBOLOGICAL BEHAVIOR OF METAL MATRIX COMPOSITE MATERIAL
For structural application of moving components, the tribological properties are considered to be one of the major factors controlling the performance. In the present study, Al-Cu-Mg alloy was used as a matrix material. Particulate Titanium dioxide was used as a reinforcing material. This investigation is carried out to understand tribological properties of as cast Al alloy and TiO2 reinforced Al alloy metal matrix composite. Dry sliding wear test was conducted to understand the tribological behaviors of the test samples. A pin-on-disc type test rig was used to evaluate the wear behavior of the composite. Addition of hard Titanium dioxide to Aluminum alloy results in enhancement in the hardness of the composites. Increased hardness leads to lowering of wear loss and seizing.
Tribological behavior and wear surface analysis of metal-matrix composites
1999
This paper describes the results of dry sliding wear tests and wear surface analysis of boron-fibre-reinforced aluminium composites. The wear tests were conducted for normal and parallel orientations, rubbing against a rotating steel disc at different loads at speeds of 0.6 and 1.6 m s −1. In addition, the wear surface analysis of the aluminium-based composites was investigated by X-ray photoelectron spectroscopy (XPS). The metal-matrix composites showed excellent wear resistance compared with the unreinforced matrix. Fibre orientation had a small effect on wear rate: at low speed the normal orientation gave the lowest wear rate, with the performance of the parallel orientation being slightly worse, but this trend reversed at high speed. The XPS analysis revealed that there was no significant variation in the amount of oxide over the surface under the test conditions used. At low speed in the normal orientation boron oxide and iron boride were formed, while at high speed the proportions of these components were slightly different and showed alloyed material with more iron boride and aluminium but less boron in total.
A Review on Processing and Tribological Properties of Metal Matrix Composites
Metal matrix composites are widely used in automotive, marine and aerospace applications. These composites exhibits superior properties like high strength to weight ratio, good wear resistance, and corrosion resistance and enhanced fatigue properties compared to monolithic materials. Several matrix materials like aluminium, magnesium, copper and titanium are widely used to prepare metal matrix composites. Reinforcements in the form of fibres, whiskers and particulates can be used into matrix. Most commonly used reinforcements are SiC, B 4 C, graphite, TiC and Al 2 O 3 in the form of particulates or fibres. Metal matrix composites are fabricated by stir casting, powder metallurgy, diffusion bonding or by in situ process. Many researchers have been investigated the mechanical and tribological properties of metal matrix composites. For industrial applications tribological properties like wear and friction plays very important role. S o, in this paper an attempt has been made to review ...
Improvement of Tribological Properties of Metal Matrix Composites by Means of Slide Burnishing
Burnishing of metal surfaces can affect positively tribological and mechanical properties such as fatigue strength, wear resistance, contact stiffness and bearing capacity. Burnishing affects the entire surface topography, including surface roughness, radii of curvature of peaks and valleys, slope angles and more. We have studied A1Mg1SiCu (6xxx series) aluminum matrix composites with a reinforcing phase of Al2O3 which exhibits good workability but poor machinability. The second series studied was based on an AlSi alloy (A-390) reinforced with SiC – this one characterized by poor workability but good machinability. Materials have been prepared by mixing metal powders with the reinforcement, cold pressing, sintering, hot extrusion and heat treatment. We have determined surface roughness with a Hommel tester; the arithmetical mean for A1Mg1SiCu (A6061 + Al2O3) was ~1 μm before burnishing and ~0.15 μm after burnishing. We have also determined the bearing capacity at 50 % with the same tester: before burnishing 2.30 μm and 0.47 μm afterwards for A6061 + Al2O3; before 2.30 μm, afterwards 0.37 μm for A390 + SiC. Vickers microhardness at the surface with respect to the core increases 30 % for the Al2O3 containing composite and 50 % for the SiC containing composite.
Tribological properties of composite working under dry technically friction condition
AbstrAct Purpose: The article presents the research results on tribological properties (friction coefficient, wear) of the frictional couple cast iron-composite. The subject of that research was aluminium heterophase composites containing two carbide phases: chromium (Cr 3 C 2 ) and titanium carbides (TiC). Design/methodology/approach: The friction process was conducted on a tribological pin-on-disc tester (T-01M) under technically dry friction conditions. Findings: The results of friction and wear coefficients' investigation allowed the determination of how the volume fraction of NiCr/Cr 3 C 2 +TiC composite powder can influence on the course and degree of cast iron and composite wear. Practical implications: An increase in the reinforcing phase fraction allowed the elimination of the phenomena connected with adhesion wear. The 10% fraction of a carbide reinforcing phase ensures a uniform wear mechanism and has a beneficial influence on the operation of the tribological couple: cast iron -heterophase composite, during which no negative effects of increased wear of the cooperating material are observed. Originality/value: The application of heterophase reinforcement is a solution which to a large extent enables the broadening of the possibilities to design and diversify the tribological properties of friction couples.
Influence of the solid lubricant particles reinforcement on composites tribological properties
Proceedings of the 11th International Conference on Tribology – SERBIATRIB ‘09
Because of their favourable properties composite materials with reinforcements are used in many industries. With the aim to additionaly improve some of their properties, especialy their tribological properties several solid lubricants are used in the process of composite production. Many authors have analysed an influence of different reinforcements on mechanical, thermal and tribological properties of metal matrix composites (MMCs). This paper gives an overview of investigations and possibilities of solid lubricant particles (such as graphite) applying as composite reinforcements mainly for aluminium base omposites that are nowdays common in use in automotive and aeronautics industry. Based on presented experimental results of tribological properties one can find some remarks and conclusions that could be useful for further investigation of solid lubricants applying in MMCs production.
Latest progress on tribological properties of industrial materials
Materials & Design, 2014
Wear is closely related to friction and lubrication; the study of these three subjects is known as tribology. In science and technology it is concerned with interacting surfaces in relative motion. Soft or hard film coating, alloying and composite structuring have all been developed to control wear and friction. This is achieved by improving materials and surfaces with some characteristics that improve resistance to friction and wear. In recent years, several new solid lubricant and modern lubrication concepts have been developed to achieve better lubricity and longer wear life in demanding tribological applications. Most of the traditional solid lubricants were prepared in the form of metal, ceramic and polymer-matrix composites. They have been used successfully in various engineering applications. Recent progress in thin-film deposition technologies has led to the synthesis of new generations of self-lubricating coatings with composite or multilayered architectures, by using multiplex surface treatments. In this study, typical wear behaviors of representative materials of metallic alloys, ceramics, polymeric materials, and composites are reviewed in relation to their friction behaviors. Additionally, modeling for the wear prediction is outlined.
Materials Today: Proceedings, 2021
Global issues related to the scarcity of natural (or monolithic) materials need extensive research in the field of materials science. Aluminum (Al) and magnesium (Mg) based hybrid metal matrix composites (HMMCs) having properties like a light in weight, better stiffness, hardness, strength to weight ratio, and wear resistance are the best alternatives and has fulfilled the existing problems in all aspects of engineering and medical applications so far. 'Tribology' is an important mode which deals with the interlinked study of friction, wear and lubrication of interacting surfaces in relative motion to examine the tribological properties of fabricated composites. This article provides all the significant attributes of tribological behavior of HMMCs, based on the critical review of the existing literature, stir casting found to be the best fabrication technique, and pin on disc tribometer for the wear analysis is highly recommended for Al and Mg-based HMMCs.
Aluminum/Graphite (Al/Gr) composites have been used as self-lubricating materials due to the superior lubricating effect of graphite during sliding. This paper summarizes various tribological aspects of self-lubricating aluminum composites. The influence of various factors such as (a) material factors – graphite size and volume fraction, and (b) mechanical factors – applied load and sliding speed on the tribological properties of self-lubricating aluminum composites are discussed. Furthermore, the tribological properties of self-lubricating composites as a function of these parameters and the active wear mechanism involved in various systems are discussed. Bringing self-lubricating composites into different operating systems is a solution to reduce the use of external toxic petroleum based lubricants in sliding contacts in a way to help the environment and reduce energy dissipation in industrial components for strategies toward sustainability and energy efficiency.