Metal Matrix composites

Abstract: Now a days, Metal matrix composites have been regarded as one of the most proposition grouping in composite materials. There is lot of demand in the modern society from the working life in aluminum metal matrix composites. The best example for this is application of the aluminum and its alloys as substitution for steel and similar materials. Specific aluminum alloys have good mechanical properties, but poor Tribological characteristics. The thermal characterization of hybrid metal matrix composites has imperative impact in a wide range of applications. The thermal conductivity is the most important properties of Metal Matrix Composites (MMCs). Since nearly all Metal Matrix Composites are used in various temperature ranges, measurement of thermal properties of MMC’s as a function of temperature is necessary in order to know the behavior of the material. Thermal conductivity is one of the primary terms commonly used in the research of materials. The thermal characterization of composite materials has received large consideration and has become governing in materials science and engineering. In this paper, the thermal conductivity investigation of Al6351, Sic and Gr. hybrid metal matrix composites by varying percentage reinforcement of Sic (0,2,4,6,8,10%) and Gr.(10,8,6,4,2,0%) have been carried out. Al based composite reinforced with Sic and Gr. particle have been prepared by squeeze casting technique. The main advantage of going for squeeze casting is the material wastage is less and the low level of porosity. The investigation of thermal conductivity behavior of hybrid composites with var ying percentage reinforcement at lower division have been emphasized.

Abstract: Metal Matrix Composites are the ground-breaking materials that possess unrestrained opportunities for modern material science and development. These materials satisfy the desired conceptions, objectives and requisites of the designer. The reinforcement of metals can have many different objectives. Reinforcements for metal matrix composites have a diverse demand outline, which is determined by production and processing and by the matrix system of the composite material. The reinforcement of light metals will have profuse prospect of application areas where weight reduction has first priority. This material group becomes motivating for the utilization as constructional and functional materials, if the property contour of the conventional materials either does not arrive at the increased standards of explicit demands, or is the solution of the problem. However, the appreciative technology of MMCs is in competition with other modern material technologies. In the present scenario, researchers and scientists are fascinated and involved in exploring new developments pertaining to metal matrix composite materials. Numerous scientists and researchers have carried out an extensive research work on mechanical and tribological behaviours of composite materials because of appreciative and advantageous properties. In present circumstances, Metal Matrix Composites are primarily important for military, automotive and aerospace applications. In the research work, Aluminium based composites reinforced with Silicon Carbide and Graphite particles have been prepared by stir casting technique.

Vinoth M.A, Arun L.R, Bhimagoud Patil [3] in their paper, “The Fabrication Process and Mechanical Characterization of Pure Al- Si Mmc’s for Engine Applications” investigated the fabrication of aluminium-silicon based hybrid metal matrix composites reinforced with silicon carbide and cenosphere particulates for engine applications. Pure Al-12.5 weight % Si alloy reinforced SiC & cenosphere particulates were produced by using stir casting technique. These materials were developed for piston, cylinder sleeve and engine blocks.

This paper deals with an experimental study on the grindability of Al/SiC metal matrix composites in cylindrical grinding. Machining of metal matrix composites (MMCs) is an area to be focused and finishing processes such as grinding to obtain a good surface finish and damage-free surfaces are crucial for the application of these materials. Nevertheless, grinding of MMCs has received little attention so far, thereby a detailed study on that has been carried out. In the present work, experiments are carried out to study the effect of grinding parameters; wheel velocity, work piece velocity, feed and depth of cut and SiC volume fraction percentage on the responses; grinding force, surface roughness and grinding temperature. Surface integrity of the ground surfaces is assessed using a scanning electron microscope (SEM). There are no cracks and defects found on the cylindrical ground surfaces at high wheel and work piece velocities, low feed and depth of cut.

Uvarajaet .al [14]observed that Hybridization is commonly used for improving the properties and for lowering the cost of conventional composites. Hybrid MMCs are made by dispersing two or more reinforcing materials into a metal matrix. They have received considerable research and trials by Toyota Motor Inc., in the early 1980s. Hybrid metal matrix composites are a relatively new class of materials characterized by lighter weight, greater strength, high wear resistance, good fatigue properties and dimensional stability at elevated temperatures than those of conventional composites. Due to such attractive properties coupled with the ability to operate at high temperatures, the Al matrix composite reinforced with SiC and B4C particulate are a new range of advanced materials. It was found that applications of hybrid composites in aerospace industries and automobile engine parts like drive shafts, cylinders, pistons and brake rotors, consequently interests in studying structural components wear behaviour. . Anand Kumar et.al research work carried out by Addition of reinforcement such as TiC, SiC, Al2O3, TiO2, TiN, etc. to Aluminium matrix for enhancing the mechanical properties has been a well–established fact. In-situ method of reinforcement of the Aluminium matrix with ceramic phase like Titanium Carbide (TiC) is well preferred over the Ex–situ method. In the present investigation, Al-Cu alloy (series of 2014 Aluminium alloy) was used as matrix and reinforced with TiC using In-situ process. The Metal Matrix Composite (MMC) material, Al-.5%Cu/10%TiC developed exhibits higher yield strength, ultimate strength and hardness as compared to Al-4.5%Cu alloy. Percentage increase in yield and ultimate tensile strengths were reported to be about 15% and 24% respectively whereas Vickers hardness increased by about 35%. The higher values in hardness indicated that the TiC particles contributed to the increase of hardness of matrix.

Day by day the researchers are proposing a lot of new metals for different applications with unique properties. It is not an ease of work to alter the properties and behaviour of monolithic metals. But it is possible in case of Metal Matrix Composites. Hence MMCs attracts the researches and industries to concentrate on it. So it is strongly believed that composites are better alter for monolithic metals [1]. In order to get better surface finish and dimensional accuracy it has to be machined. Due to the presence of hard reinforcements in the composites and extensive tool wear, it is very difficult to machine through conventional process [2]. To overcome this drawback the industries are preferring for non-traditional machining process. Tool wear and power consumption for machining is predominantly depends on reinforcement particle size and volume fraction [3]. Many researchers are showing their interest on Electrical Discharge Machining (EDM), ECM among the other non- traditional processes. EDM works based on the erosion principle. Repeated spark is produced on workpiece to melt locally [4]. To increase the Metal Removal Rate (MRR) and better surface finish, electrically conductive particles are mixed with dielectric fluid [5].

Metal matrix composites have mainly preferred because of its good specific strength. Reinforced metal matrix composites have been gaining its positive effects due to its low cost. Cast aluminium has good wear resistance among many methods. stir casting is the cheapest way to produce. Problem associated with it is that particulates are non- uniformly distributed due to very low wettability. Taguchi design of experiments is an effective way which can be employed for analyzing the frictional force and dry sliding wear of composites by Ajay[1]. Al6061 can be successfully synthesized from stir casting technique [2]. From the research it is concluded that increase in load leads to maximum on wear volume loss by Chowdhury [4]. Wear generally occurs when two body comes in contact with each other. The weakness of material leads to rupture due to repeated action. wear can be of various types they are of abrasive, corrosive, surface fatigue. Wear rate gradually increases with applied load. Taguchi based experimental designs proves to be highly productive as it reduces the number of experiments there by reducing the cost as well as time for experiment but it fails to optimize the multiple objective . In order to overcome this problem various researchers have employed various theories along with Taguchi method to achieve multi response optimization by Issam Hanafiet.a(2012),Rajmohan et.al (2013) and Krishnamoorthy et.al.(2012The purpose is to

The present work was intended to estimate thermoelastic behavior of AA2024/magnesium oxide nanoparticle metal matrix composites. The RVE models were used to analyze thermo-elastic behavior. The stiffness of AA2024/ magnesium oxide nanoparticle metal matrix composites decreased with the increase of temperature. Below 0 o C and above 100 o C MgO nanoparticles were fractured except in range of 0 o C to 100 o C where the interphase has fractured.

Aluminum metal matrix composites (AMCs) are potential materials for different applications because of their great physical and mechanical properties. The expansion of reinforcements into the metallic composites enhances the solidness, explicit quality, wear, creep and weakness properties contrasted with the regular designing materials. This paper exhibits the review of the impact of expansion on various reinforcements in aluminum composite featuring their benefits and bad marks. Significant issues like agglomerating marvel, fiber-lattice holding and the issues identified with dispersion of particles are talked about in this paper. Impact of various reinforcements on AMCs on the mechanical properties like elasticity, strain, hardness, wear and weariness is likewise talked about in detail. Real uses of various AMCs are likewise featured in this work.

Fly ash particles are potential discontinuous dispersoids used in metal matrix composites due to their low cost and low density reinforcement which are available in large quantities as a waste by product in thermal power plants. Addition of fly ash particle as reinforcement in MMCs is advantageous for obtaining higher structural homogeneity with minimum possible porosity levels, good interfacial bonding, higher mechanical strength, uniform distribution of reinforcement and act as a load bearing constituents 28-31 . The major constituents of fly ash are SiO 2 , Al 2 O 3 , Fe 2 O 3 , and

A composite material is produced from two or more constituent materials with significantly different physical or chemical properties. The constituent materials, then work together to give the composite unique characteristics that are different from the individual components. The individual components remain separate and distinct within the finished structure as they do not blend or dissolve into each other. Wood is an example for natural composite, made from long cellulose fibers (a polymer) held together by a much weaker substance called lignin. The bone in the human and animals' body is also a natural composite. It is made from a hard but brittle material called hydroxyapatite (which is mainly calcium phosphate) and a soft and flexible material called collagen (which is a protein). The terms of matrix and reinforcement are very often used when talking about composites. Matrix is a relatively ‘soft’ phase with specific physical and mechanical properties, whose sole purpose is to bind the reinforcements together by virtue of its cohesive and adhesive characteristics, to transfer load to and between reinforcements. The reinforcement phase (or phases) is usually stronger and stiffer than the matrix and mainly carries the applied load to the composite [5]. Composite materials can be subdivided into three main groups: Polymer, Ceramics and Metals. Reinforcements added to these materials produce Polymer Matrix Composites (PMC), Ceramic Matrix Composites (CMC) and Metal Matrix Composites (MMC). Among different composites, Metal–matrix composites are the most widely used in the industrial scale due to its advantages compared to Polymer Matrix Composites and Ceramic Matrix Composites.

The emergence of metal matrix composites is partly a consequence of an improved understanding of their potentials and limitations based on their science of process, principles of physical metallurgy and interfacial chemistry. They can be produced by conventional casting techniques. The reinforcing material such as particulates of graphite can be added into the melt of any metal during its stirring. The resultant mixture is then cast into a permanent mould. This technique was used to produce aluminum-graphite composite containing different percentage concentrations of graphite ranging from zero to twenty (0-20%wt). To solve the problem of making the molten aluminum alloy wetting the graphite, a special chemical activation was carried out. The accent is on mechanical performance, describing how the presence of reinforcement in a metallic matrix influences its mechanical and physical properties. This composite shows a decrease in wear rate due to the presence of graphite in the composite.

Engineering applications require materials that are stronger, lighter and less expensive. A good example is the current interest in the development of materials that have good strength to weight ratio suitable for automobile applications where fuel economy with improved engine performance is becoming more critical. Metal matrix composites (MMCs) have been noted to offer such tailored property combinations required in a wide range of engineering applications [1]. The Metal matrix composites are combination of two or more than two different materials including metal, inter metallic compound or next step dispersed phase of metal matrix. To achieve optimum combination of properties it has produced by controlling the morphology of constituent. The properties of Constituent’s phase, its relative amount, dispersed geometry including particle shape and size along with orientation in matrix The aim involved in designing metal matrix composite materials is to combine the desirable attributes of metals and ceramics. The addition of high strength, high modulus refractory particles to a ductile metal matrix produce a material whose mechanical properties are intermediate between the matrix alloy and the ceramic reinforcement. Composite materials consist of matrix and reinforcement. Its main purpose is to transfer and distribute the load to the reinforcement or fibers. This transfer of load depends on the bonding which depends on the type of matrix and reinforcement and the fabrication technique[2]. The matrix can be selected on the basis of oxidation and corrosion resistance or other properties. Generally Al, Ti, Mg, Ni, Cu, Pb, Fe, Ag, Zn, Sn and Si are used as the matrix material, but Al, Ti, Mg are used widely.[3].

ABSTRACT: The applications of aluminium and its alloys can be found in almost every engineering field such as aerospace, marine, automotive, structural and various other fields. Due to its versatile properties it is preferred for fabricating different types of metal matrix composites. Metal matrix composites exhibit better and improved strength, toughness, formability, corrosion resistance, machinability, stiffness, wear, creep, fatigue and numerous other mechanical properties as compared to metals. With the invention and development of these aluminium metal matrix composites various drawbacks faced by the engineering society have been overcome and best possible solutions are provided. This review paper mainly focuses on the mechanical behavior of various types of aluminium metal matrix composite developed using different fabrication techniques. Main emphasis is on the study of wear behavior of AMMCs with various input conditions, prepared using stir casting process as it is one of the predominantly used fabrication technique.

ABSTRACT: Aluminium alloys are widely used in automobile industries, Ship-yard and aerospace applications due to their great mechanical properties, low density, low coefficient of thermal expansion, better corrosion resistance and wear as compared with conventional metals and alloys. The low production cost and better mechanical properties of composites makes them very useful for various applications in many areas from technological point of view. The aim involved in designing aluminium based metal matrix composite by combining different percentage of particulates in the mixture. Present study is focused on the fabrication of 2024 aluminium based metal matrix composites reinforced with boron carbide, graphite by stir casting technique to determine Hardness, Tensile strength and microstructure of the metal matrix was performed on the samples obtained by stir casting technique.

In the present investigation, aluminum based hybrid metal matrix composites containing 5, 10 and 15wt% SiC and Fly-ash particulates of 53µm were successfully synthesized by vortex method. The matrix materials used in this study was Al-Si alloy (A356) whose chemical composition was shown in table 1

The presence of hard abrasive particles limits the machinability of MMCs and consequently they have limited applications. Both conventional and unconventional machining processes have been used for machining of MMCs. The factors that affect the machinability of MMCs are work material, percentage of reinforcement, tool material, tool profile and cutting parameters like cutting speed and feed rate. Unconventional machining processes like Electric discharge machining (EDM), powder mixed-EDM, wire-EDM, abrasive water jet machining have been employed in the recent year for machining of MMCs. However, there material removal rate is significantly less as compared to the conventional machining processes. The present research investigation explore the research challenges in the secondary processing of metal matrix composites particularly in drilling behavior of metal matrix composites.

Al and Al alloy based composites have been characteristics as futuristic materials for a number of engineering purposes. And the material are more preferred by engineers because of their great strength, low density, enhanced and tailored high refractoriness properties, stiffness and damping capabilities. The principle advantage is that MMCs can be use to a significantly higher temperature. Increasing quantities metal matrix composites MMCs being used to replace conventional materials in numerous applications, especially in the automobile and recreational industries. MMC's provide a better combination of Specific strength and modulus compared to monolithic alloys like aluminum, magnesium, copper, nickel and steel in relevance, commonly light weight and energy savings are essential design considerations. In recent years there was a great deal of interest in particulate- reinforced metal-matrix composites (MMCs), and in particular those based on existing aluminum alloys.

The drill wear measurement is a complex phenomenon as compared to other cutting tools. The tool wear depends upon the tool material, workpiece material, cutting conditions and temperature generated at the tool workpiece interface. The various tool wear mechanism responsible for tool wear are; two body or three body abrasions, adhesion, diffusion and plastic deformation of the cutting edges. Flank wear, crater wear, rupture of cutting edge or groove formation are commonly observed on drill geometry when working with metal matrix composites. The quality characteristics like surface roughness, burr formation and the dimensional accuracy are governed by the tool wear. The abrasion wear of flank face is predominant cause of tool wear in drilling of MMCs [2, 4].

Metal matrix composites (MMCs) materials are presently undergoing active development in the whole world. The benefits of using MMCs materials lie in the advantage of attaining properties combination that can result in a number of service benefits. The development of MMCs may encompass primary issues like selection and distribution of constituent phases, the characteristics of the interface and the possible tailoring of constituents. There are numerous production methods available for production of the MMCs materials; there is no unique route in this respect. Owing to the choice of matrix material and reinforcement and of the type of reinforcement, the production methods can vary substantially. Processing of MMCs can be classified according to whether the matrix is in solid, liquid, or vapor phase while it is being combined with the reinforcement. The present paper explores the various techniques used by the researchers for the production of metal matrix composites.