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Fabrication and Electrical Discharge Machining of Al-SiC-Mg Composite with Mechanical Characterisation

Composites are the materials obtained by combinations of different materials, with greater and better properties that are not present in the individual parent material. Due to its outstanding properties like light weight, corrosion resistance, higher strength and better thermal and electrical properties it is widely used. More than 40000 products of composite materials are used across the Globe. In this work Aluminium Metal Matrix Composite is formed with varying percentage of SiC and Mg. The electrical discharge machining (EDM) of the fabricated composite material has done to observe the material removal rate (MRR) and surface roughness along with different tests such as XRF, hardness test, tensile test and compression test. This paper represents the information that are observed after conducting various tests on composites casted by varying the percentage of Sic and Mg.From Various tests it is observed that with increase in percentage of SiC and Mg hardness, Young’s modulus and MRR increases
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  • 1. www.ijemr.net ISSN (ONLINE): 2250-0758, ISSN (PRINT): 2394-6962 88 Copyright © 2018. IJEMR. All Rights Reserved. Volume-8, Issue-5, October 2018 International Journal of Engineering and Management Research Page Number: 88-99 DOI: doi.org/10.31033/ijemr.8.5.04 Fabrication and Electrical Discharge Machining of Al-SiC-Mg Composite with Mechanical Characterisation Kula Bhusan Pradhan1 , Biswajit Nayak2 and Sudeep Kumar Singh3 1 PG Scholar, Department of Mechanical Engineering, Centurion University of Technology and Management, Odisha, INDIA 2 Associate Professor, Department of Mechanical Engineering, Centurion University of Technology and Management, Odisha, INDIA 3 Associate Professor, Department of Mechanical Engineering, Centurion University of Technology and Management, Odisha, INDIA 1 Corresponding Author: kulabhusan121@gmail.com ABSTRACT Composites are the materials obtained by combinations of different materials, with greater and better properties that are not present in the individual parent material. Due to its outstanding properties like light weight, corrosion resistance, higher strength and better thermal and electrical properties it is widely used. More than 40000 products of composite materials are used across the Globe. In this work Aluminium Metal Matrix Composite is formed with varying percentage of SiC and Mg. The electrical discharge machining (EDM) of the fabricated composite material has done to observe the material removal rate (MRR) and surface roughness along with different tests such as XRF, hardness test, tensile test and compression test. This paper represents the information that are observed after conducting various tests on composites casted by varying the percentage of Sic and Mg.From Various tests it is observed that with increase in percentage of SiC and Mg hardness, Young’s modulus and MRR increases. Keywords— Composite, EDM, MRR, XRF I. INTRODUCTION Now a days everyone wants the material which are having high strength, greater stiffness, better wear resistance, good machinability, desired hardness with superior toughness and attractive look. But all of these properties are not present in a single metal or material, In order to get these properties in a single piece of metal or material we are using some advanced Engineering processes, by applying these processes different parent materials having different properties are combined together either Mechanically or Metallurgically and the combined product shows the superior and better properties that are not present in the parent metals, these combined materials or product with greater and better properties are called as Composite Materials. From the historical back ground we can know that the man kind first learn how to create the fire and how to control the fire. Then the man kind invented the wheel and the most important development was spinning of continuous yarn which enables them to survive outside the tropical climatic zones and spread over the maps of the earth. Cotton and Jute and more natural resources were used as flexible Fabrics then and this process had resulted in the First Composite. Then Wood and straw were used to make the wallswith mud and wood layers were used to make the Roofs. From some sources it is known that towards the second half of the 20th Century in order to avoid the technical problems due to the use of heavier materials, some light weight composites were used. Nowadays we are focusing on cost reduction during manufacturing and operation, with a more Environmental friendly Design, which leads to the more use and production of Composite Materials. Nowadays in every field the application of composite is increased by numbers and by volumes starting from the use of a shaving blade to the space suits for Astronauts. Fibres or Particles Embedded in materials of another material are the best example of Modern Day composite materials. When different layers of Fibrous composite materials are combined one above another it
  • 2. www.ijemr.net ISSN (ONLINE): 2250-0758, ISSN (PRINT): 2394-6962 89 Copyright © 2018. IJEMR. All Rights Reserved. forms the Laminates. Laminates are the composite materials having a specific function to perform. The Individual layers consist of high modulus and high strength fibres in matrix materials. Fibres like Silicon Carbide , cellulose, graphite glass and Boron are used. Matrix materials like Aluminium , Titanium and Alumina are used. Generally the Composite Materials are consist of Two Phases. One Of Its constituents is called reinforcing Phase . The materials in this phase are in the forms of Fibre, PrticlesOr Flakes. The Other phase is known as Matrix phase in which reinforcing phase materials is embedded. The matrix phase materials are generally Continuous. The Reinforcing phase is strong and hard and may not be light in weight. The matrix but is light but weak. Work Of the reinforcement Phase: It provides high strength, stiffness and other improved Mechanical Properties to the Composite. Also Contributes Towards the Properties of a Co Efficient of Thermal Expansion, Conductivity, Etc. Work of The Matrix phase: The required shape is achieved by matrix phase. The Fibres are Kept in place by Matrix Phase. Matrix phase also transfers Stresses to the fibres . The protection from the Environment , Chemicals, Moisture To the Reinforcement is Provided by the Matrix Phase. Mechanical Degradation of Fibres surface are also protected. It also act as shielding from damage caused due to handling. When the matrix of the composite material is a metal or an Alloy , the Composite is known as Metal Matrix Composite or MMC. Aluminium Metal Matrix Composite (AMCC) used Aluminium or its Alloys as their Matrix Phase. Generally Aluminium metal matrix composites are refer to the class of light weight and high performance composite materials. Continuous and dis continuous Fibres can be used as reinforcement in AMCC. According to the need of Industrial applications the properties of AMCC can vary by suitable combination of Matrix, Reinforcement and Processing Methods. For an given composite material it is desired that the reinforcement should stable in the given working Temperature and should not react. In order to Increase the Tensile Strength, Hardness, Density and Wear Resistance of Aluminium and its Alloys most commonly Silicon Carbide(SiC) is used as reinforcement. Aluminium Oxide (Al2o3) also used as Reinforcement for AMMC. Aluminium is a chemical element with symbol Al and Atomic Number 13. It is a ductile Material having Melting point of 660.3 and Boiling point of 2470 with a density of 2830 Kg/m3. It is a Silvery-White , soft, non magnetic and Ductile Metal in the Boron Group. By Mass Aluminium makes up about 8% of the Earth’s Crust. It is the Third Most Abundant Element After Oxygen and Silicon and the most abundant metal in the crust. The Pure form of Aluminium is relatively highly corrosion resistance. The Mechanical strength achieved by suitable alloying and heat treatment process. It is having low density. These three main properties increases the importance of applications of Aluminium in the whole World. With the above main properties the Aluminium also includes some important properties like High Electrical and Thermal Conductance, Good Reflectivity, High Ductility, Low working cost, magnetic Neutrality, high scrap value and non-poisonous and colourless nature of its corrosion products which makes it suitable for use in Chemical and food processing Industries. In its Pure State Aluminium is relatively a soft metal with a Yield Strength of 34.5 N/mm2 and a Tensile Strength of 90 N/mm2. By the development of wide range of alloys varied strength and ductility can be achieved. So its use is ranges fromuse of very thin foil material in the packaging industry, ductile material for Drink Containers, highly conductive alloys for Electrical Purpose, Relatively low strength alloys for Building Industry and High Strength Materials for Air Craft and Armoured Vehicles. The main classes of Aluminium Alloys are the 2000 Series (Al-Cu Alloys) which are high strength materials used in aircraft Industry. The 3000 series (Al-Mn Alloys) used mainly in the canning Industry, the 5000 series (Al-Mg Alloys) which are used unprotected for structural and architectural purposes. The 6000 series (Al- Mg-Si alloys) which are the most common extrusion alloys and are used particularly in the Building Industry and the 7000 series (Al-Zn-Mg alloys) which are again high strength alloys for aircraft and military vehicle applications. Silicon Carbide Also known as carborundum is a Semi-conductor containing Silicon And Carbon With Chemical Formula SiC. Silicon Carbide Occurs naturally as the rare mineral moissanite. Silicon Carbide is prepared by Acheson Method in which pure silica sand (SiO2) and Finely Ground Coke (Carbon) are mixed together and heated to very high temperature in an Electric Furnace. It is having an High Melting Point Of 2,730 with a Density of 3,210 Kg/m3. Silicon Carbide has been recognized as an important ceramic material because of its uniqe combination of properties such as Excellent Oxidation Resistance, Strength Retention to High Temperature, High wear Resistance , high thermal conductivity and good thermal shock resistance. Such Properties are obtained by Highly Covalent (upto 88%) Chemical Bonding between Silicon and Carbon Atoms. Silicon Carbide is widely used to make various materials such as sand papers, grinding wheels, cutting tools, hard ceramics, refractory linings, high temperature
  • 3. www.ijemr.net ISSN (ONLINE): 2250-0758, ISSN (PRINT): 2394-6962 90 Copyright © 2018. IJEMR. All Rights Reserved. bricks, wear resistant parts of pump and rocket engines and also in Jewellery. It is also used to Manufacture Light Emitting Diodes(LEDs) and Semi-conductor Devices. Magnesium Belongs to Group 2 of the Periodic Table. The Element has an Atomic Number of 12 and Atomic Mass of 24. Magnesium is a Chemical Element With Symbol Mg. Magnesium is the Eighth abundant element in the Earth’s Crust with an average of 2.76%. The Mg2+ ion is the second Most Abundant Cat ion in Sea Water after Na+. It is having the Melting Point of 650 and Boiling Point of 1,090 with a Density of 1.74 g/cm3. Magnesium appeared as a silvery- white metal that ignites easily in air and burns with a bright light. Magnesium is one third less dense than Aluminium. It improves the Mechanical , Fabrication and Welding Characteristics of Aluminium when used as alloying agent. These Alloys are useful in Aeroplane and Car Construction. Magnesium is used in Products that benefits from being light weight such as Car Seats, Luggage, Laptops. Cameras and Power Tools. Magnesium Hydroxide is added to plastics to make them fire retardant. Magnesium Oxide used to make Heat Resistant Bricks For Fire Places and Furnaces. Nowadays composites are widely used materials. In manufacturing of Automobile Parts. In Heavy Transport Vehicles and Commercial Aircraft Applications. Used For Manufacturing of Bearings, Rotors and Compressors. Typical Applications in Air Craft Industry: Landing Gear Doors, Elevators, Rudder Fairings, Trailing Edge Flaps, Turbine Blades, Turbine Shafts, Fly Wheels and Rotor Shafts in Helicopters. Typical Structural Applications: Door Shutters, Doors, Window Frames, Ceilings, Door Hinges, Panelling, Roofing, Pipes, Water Storage Tanks, Tunnel Supports, Roads, Bridge Structures, Marine and Offshore Structures and Concrete Slabs. Applications in Power Transmission: Composite Power and Lighting Poles, High Voltage Electrical Transmission Towers. Miscellaneous: Automobile Engines, Piston, Cylinder, Connecting Rod, Crankshaft Etc. Also Used To Manufacturing The Plumbing Components. Today More than 40000 products of Composite Materials are used across the Globe. Composites are versatile Product. Their Properties are: High strength to weight ratio, Light Weight, Fire Resistance ,Good Electrical Properties, Chemical And Weathering Resistance, Desired Colour, Translucency ,Design Flexibility, Manufacturing Economy, High Fatigue Resistance ,High Impact Strength, Thermal Insulating Properties Mao [1] has studied the dependent of gear performance on load. He noted that a sudden transition to high wear rates when the transmitted torque is increased to a critical value. This happens because the gear surface temperature of the material is reaching its melting point. He observed that for a given geometry of actual gear, a critical torque can be decided from its surface temperature calculation Mao [2] adopted the numerical approximation using finite different method for the analysis of the flash temperature for polymer composite gears. Also he has compared the results obtained by using semi-analytical method assuming no internal hysteresis and the material properties are constant. Yakut et al [3] has investigated the Load carrying capacity and occurring damages of gears which are made of PC/ABS blends. In this study, usability of PC/ABS composite plastic materials as spur gear was investigated. Moya and Machado [4] performed a theoretical analysis of the procedure to determine the Lewis Factor and also performed the contact analysis of spur gears to find the stress distribution between gear teeth. Tsai brothers [5] established a characterization method for seven polyamide (PA) grades to determine the major material to manufacture an automotive worm gear. They measured the properties of the composite according to the worm gear loadings: tensile strength, Young's modulus, abrasion and impact resistance. The properties were also correlated to the PA moisture absorption and its glass fiber (GF) reinforcement. Acilar and Gul [6] investigated a composite with Al–8.7 wt. % Mg matrix alloy reinforced with SiCp. It was added as dispersed particles by Vortex method. Better distribution of SiCp was obtained in matrix Dong et al [7] studied the as-cast microstructures, the evolution of the microstructures during reheating, and the mechanical properties of thixoformed products of 7075 Al alloy cast by liquid us semi continuous casting (LSC). Mitra et al [8] prepared the Al matrix composites reinforced with unoxidized or oxidized SiC and varying Mg concentrations were prepared using stir casting technique. The alloying of Al matrix with 0.5 or 1 wt.% Mg and its segregation at the interfaces has been found to be effective in restricting the formation of the Al4C3 at the interfaces during casting. Mondal and Mukhopadhyay [9] studied the Al alloys, encompassed by AA 7055 alloy composition, having the nominal zinc content (i.e., 8 wt.%) but varying copper and magnesium contents across the alloy composition range they were examined in the as-cast form by a combination of light microscopy, scanning electron microscopy (SEM), electron probe microscopic analysis (EPMA), and X-ray diffraction (XRD). HUDA Z et al [10]The heat treatable 2024-T3 Al alloy were characterized by the use of modern metallographic and material treated techniques (e.g., EPMA and SEM). The micro structural characterization of the metallographic specimen involved use of an optical
  • 4. www.ijemr.net ISSN (ONLINE): 2250-0758, ISSN (PRINT): 2394-6962 91 Copyright © 2018. IJEMR. All Rights Reserved. microscope linked with a computerized imaging system using MSQ software. J.Hasihm [11] Successful fabrication of aluminium matrix composite by using the stir casting method has added a new dimension to the processing of cast composites. The porosity level was reduced by preheating the ceramic particles to burn off the any moisture. Micro structural observation revealed that the reduction in grain size due to the stirring action of the slurry strengthen the composite more as compared with the unreinforced alloy. Alpas and Zhang [12] At low load, corresponding to stresses lower than the particle fracture strength, SiC particles were the load bearing constituents and their abrasive action successfully transferred the rich iron layer on to the contact surface. However, wear rate of the composite was found to be lower than the unreinforced alloy in this regime. Above a critical load, the SiC particles got fractured and the delamination wear was due to de- cohesion of SiC-matrix interfaces. The wear behaviour of the composite was similar to the unreinforced matrix alloy in this regime. With the continuous increase of load, there was an abrupt increase in weak rate by a factor of 100. The SiC reinforcement was proved to be very effective in suppressing the transition to severe wear regime Martin et al.[13]The addition of the SiC particulates improved the wear resistance by a factor of two in the mild wear region, and the transition temperature was raised by approx. 50 °C. This higher transition temperature was due to the retention of the mechanical properties in the composite at elevated temperature. Heat treatments (either natural or artificial aging) did not modify substantially the wear resistance of either the composite or the unreinforced alloy. Wilson and Alpas [14] Mild to severe wear delay was observed in the composites with the addition of Al2O3 and SiC but a hybrid A356 Al composite containing SiC and graphite remained in a mild wear regime even at the highest test temperature of 460°C. The absence of severe wear phenomena in this composite contributes to the inhibition of commination and fracture by graphite entrained in the surface tribolayer. . Shipway et al [15]Particle additions have reduced the wear rate of the composites and hence delayed the transition with load from low wear coefficients to high wear coefficients. The addition of higher amount of reinforcement resulted in a reduction in wear rate and further led to the retardation of the load at which wear coefficient increases. II. FABRICATION In this chapter the process of Fabricating the Aluminium, Silicon Carbide and Magnesium (Al-SiC-Mg) Composite is Explained. Various instruments are used to prepare the composite material. This is the important stage as the operations and testing are to be done on the composite that is fabricated in this stage. The materials used are Aluminium, Silicon Carbide and Magnesium. The Details of the fabrication process are explained in the following sections. Electric Arc Furnace and the Molten Metal To fabricate the composite bar of required shape and size the solid state metals first converted into Molten state or Liquid State. In order to convert the solid metals into liquid state high temperature is required, so one Furnace is used which provides High Temperature and area as melting chamber to melt the solid metals. In this Fabrication Process An Electric Arc Furnace, 240 Volt of Zephyrs Interprices Was used as Shown in the Figure 2.1. The Required Percentage Of Weights of Aluminium, Silicon Carbide and Magnesium were taken as Constituents For The composite Materials. The Weights Of The Various Components Taken for Two Samples as Shown in the Table 2.1. Sample no Al (gm) Sic(gm) Mg (gm) 1 1000 5 6.5 2 1000 10 12 Table 2.1 Percentage of weights of Aluminium, Silicon Carbide and Magnesium The Electric arc Furnace is switched on before Five Hours of Starting of the Melting process in order to reach at a Temperature of 650 . After observing the Temperature of the Furnace On the Temperature Indicator Fitted With The Furnace small pieces of the Aluminium Sheets are put in the Furnace. Then The Temperature is Maintained at 700 to Melt The Aluminium Completely. After That The Silicon Carbide And Magnesium Powder are added to the Molten Aluminium to Prepare the mixture of different constituents. Then a temperature of 800 is maintained inside the Melting Chamber of the Electric Arc Furnace, in order to ensure the proper mixing of the Three Constituents. Now The Molten Metal Is Ready To be Poured Into The Mould Cavity. Sand Casting, Mould and Mould Cavity The Composite bars are formed
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