International Journal of Latest Trends in Engineering and Technology (IJLTET) Investigation of Vibration properties of Aluminium, Silicon carbide, Mica a Hybrid Metal Matrix Composite R Raghuram Department of Mechanical Engineering, Sri Muthukumaran Institute of Technology, Chennai, Tamil Nadu, India S Sharath Kumar Department of Mechanical Engineering, Sri Muthukumaran Institute of Technology, Chennai, Tamil Nadu, India M Shanmuga Priyan Department of Mechanical Engineering, Sri Muthukumaran Institute of Technology, Chennai, Tamil Nadu, India P Saravanan Department of Mechanical Engineering, Sri Muthukumaran Institute of Technology, Chennai, Tamil Nadu, India T Anand Associate professor, Department of Mechanical Engineering, Sri Muthukumaran Institute of Technology, Chennai, Tamil Nadu, India Abstract- Vibration is an important mechanical phenomenon where oscillation takes place about an equilibrium point. It is desirable in some cases such as tuning fork, mobile phones and loud speakers whereas the vibrational motions of engines, motors or any mechanical devices are undesirable. In metals it is an undesirable property which produces unwanted motions, wastage of energy and noises. Aluminium which is an abundant material which is widely used in structural applications because of its light weight, high tensile strength etc. if alloyed, and is easily fabricated .In recent trends, many composites of aluminium have been developed and their damping characteristics have superior property when compared to its base alloy. This project focuses on investigating the damping characteristics of aluminium silicon carbide mica a hybrid metal matrix composite which is formed by stir casting method. Three different compositions are taken by varying the percentage of mica as 1%, 2%&3%. The advantage of this composite is that it offers high damping ratio when compared to its base metal which is aluminium. The damping behavior is studied by the use of a accelerometer and data acquisition software in cantilever beam conditions. It is found that the damping ratio increases as the percentage of mica increases. Keywords – aluminium, silicon carbide, mica, vibration, stir casting, damping ratio I. INTRODUCTION Improved fuel efficiency and demand for high-strength lightweight material is increasing the demand for composites as a result of which it has started to penetrate the field of material science. This is particularly true for automotive and aerospace sectors. Wind energy suppliers, industrial suppliers etc are also increasing their use of composites. Composite materials have an increasingly important role to play in achieving the targets for fuel efficiency and reduced carbon dioxide emissions that leading automakers are aiming for. Composite material is composed of two or more distinct phases (matrix phase and dispersed phase) and has properties significantly different from those of its constituents. Many of common materials also have a small amount of dispersed phases in their structures, even so they are not referred to as composite materials since their properties are similar to those of their base constituents Vol. 5 Issue 2 March 2015 402 ISSN: 2278-621X International Journal of Latest Trends in Engineering and Technology (IJLTET) (physical properties of steel are similar to those of pure iron).Among the three different composites namely Metal Matrix Composites (MMC), Ceramic Matrix Composites (CMC), Polymer Matrix Composites (PMC), the hybrid metal matrix composite offers more advantages than the others. Aluminium matrix composites (AMCs) refer to the class of light weight high performance aluminium centric material systems. It fulfills the requirement of Greater strength, low density, Controlled thermal expansion coefficient, improved damping capabilities, improved abrasion and wear resistance. AMCs are intended to substitute monolithic materials including aluminium alloys, titanium alloys, polymer based composites; ferrous alloys are used in several applications in automotive, aerospace, rail engineering, military, marine and industrial fields. II. EXPERIMENTAL WORK A. Materials – Metal matrix composites (MMCs) are one of the most important innovations in the development of advanced material sciences. Aluminium and its alloys are widely used in the fabrication of MMCs among the various matrix materials available. Black silicon carbide and muscovite mica are selected as reinforcement materials. Silicon carbide is selected as it is an important structural ceramic material due to its unique combination of properties such as excellent oxidation resistance, high wear resistance, high thermal conductivity, good thermal shock resistance. Muscovite mica is used as second reinforcement material as it is flexible, tough having high tensile strength; it can also withstand substantial mechanical pressure perpendicular to the plane. While mica is flexible, elastic and tough, it is very soft. Mica has zero moisture absorption. This study concerns the effect of damping resistance when the content of mica is increased. Therefore 3 different compositions are formed keeping the percentage of silicon carbide (4%) constant and varying mica percentage as 1, 2 and 3 in each composition. B. Specimen preparation – The fabrication of metal matrix composites can done using various methods, stir casting technique is one such method. This technique offers wide range of shapes, larger size particles and can with stand up to up to 500 kg load, and is the least expensive method when compared to Squeeze Casting, powder metallurgy and spray casting techniques In stir casting process, the reinforcing phases are distributed into molten matrix by means of mechanical stirring. The weighed aluminium 6061ingots is taken in a graphite crucible of number 6 and size 2Kg capacity and is heated using an electric resistance furnace of 4kw power capacity at a temperature of 850°C. The required quantity of reinforcement materials are weighed in a digital weighing machine and are also kept inside the furnace, in order to increase the intermolecular bonding with aluminium. (a) (b) (c) (d) Figure.1 (a) aluminium 6061 (b) stir casting equipment (c) mica (d) silicon carbide Vol. 5 Issue 2 March 2015 403 ISSN: 2278-621X International Journal of Latest Trends in Engineering and Technology (IJLTET) Plate die of length 150mm and thickness 5mm were taken so as to prepare the specimens for vibrational analysis as per ASTM standards. The dies were cleaned using emery paper, and graphite was applied along with kerosene to prevent the cast from sticking to the dies surface. The dies were preheated to a temperature of 500°C to reduce shrinkage loss and blow holes formation when molten metal matrix was poured into it. 1% Pure Magnesium powder was added to the molten metal to compensate for the loss during heating and also to increase the wetability between the materials. By improving the wetting we can (i) increase the surface energies of the solids, (ii) decrease the surface tension of matrix alloy, and (iii) decreasing the solid/liquid interfacial energy at the dispersed matrix interface. As the temperature set in the furnace was achieved the crucible was taken out by using steel tongs, degasser powder was added to remove the impurities in the molten metal and coverall is sprinkled over the aluminium to prevent oxidization). If by any chance oxygen enters the molten aluminium during pouring into the mould, then the final casting will have bubbles which can ruin the finish of the cast shape. Figure 2. specimen for free vibration test The reinforcement materials were then added with the molten aluminium in the crucible and were manually stirred. It is then again kept inside the furnace to obtain a temperature of 850°C. After achieving the temperature a mechanical stirrer was introduced inside the furnace which rotates at 300rpm so as to distribute the reinforcement equally. The stirring was done keeping the temperature constant and was carried out for approximately 10minutes. Then the molten metal matrix composite obtained was poured into preheated die and was set to cool off for three hours. The die was then opened to obtain the sample. This procedure was repeated for the 3 different compositions and the specimens required for the vibration analysis are thus obtained. C. Testing for vibration properties – Free vibration occurs when a system is initially loaded and then even after the load is removed the body tends to vibrate until it reaches zero value. The resistance towards such vibrations is known as damping. Damping factor of a material can be determined by knowing its natural frequency along with some other parameters such as logarithmic decrement, damping ratio and critical damping coefficient. The specimen required for testing free vibration is cut out from a large plate die cast sample as per the ASTM standard. The dimensions of the specimen are as follows, length 150mm, width 20mm and thickness 5mm. ATALON free vibration testing machine is used to determine the free vibration of the material. Vol. 5 Issue 2 March 2015 404 ISSN: 2278-621X International Journal of Latest Trends in Engineering and Technology (IJLTET) Figure.3 free vibration test apparatus The apparatus consists of a Cantilever beam with mounting arrangements to hold the specimen, NI / DEWESoft Data Acquisition System – DAQ in order to input the values from the sensor to the computer in a graphical format, Accelerometer with 5 meter cable with Wax Mount which is the sensor used to detect the vibrations of the specimen. The sample is initialed weighed and is fixed in the cantilever mounting arrangement such that 30mm of the beams length is fixed at one end. The wax mount accelerometer is attached to the other end of the sample. An impact hammer is taken and is struck against the sample in order to produce vibrations. The vibrations are sensed and recorded using the accelerometer sensor A&D 3101 having sensitivity 9.8mV/g which converts the excitation into electrical signal and feeds it to the computer and the data acquisition software plots the graph between amplitude vs. time and amplitude vs. frequency based on the signal by the accelerometer sensor. After a certain time interval the vibration in the specimen comes to zero, this is due to the damping property of the material. Three sample specimens were subjected to testing in each composition and their average value was taken to compute the damping coefficient of the composites. The Logarithmic decrement is computed from the amplitudes using the following Equation Logarithmic decrement Where, X1 and X2 are the first two successive amplitudes and n is the number of cycles. The damping ratio is determined by using the Equation, In order to find out the value of damping coefficient, we need to know the values critical damping coefficient and damping ratio. The critical damping coefficient can be found by the equation is the circular frequency. fn= Natural frequency of the material which is obtained from the peak value of amplitude vs. frequency graph. The damping coefficient C is found by the equation, From the above equation, the damping coefficient for all the 3 samples of each composition is found out and there aggregate value is taken. III. RESULTS AND DISCUSSIONS A. Vibration test – Three different compositions are taken in order to determine the effect of increase in mica on the vibrational property of aluminium silicon carbide composite and their values are given below: Vol. 5 Issue 2 March 2015 405 ISSN: 2278-621X International Journal of Latest Trends in Engineering and Technology (IJLTET) Figure.4 DEWESoft Data Acquisition System The damping ratio, coefficient and other parameters are calculated using the values obtained from the free vibration test and a table containing the results of the test is made. Table -1 Variation in damping effect for different compositions s.no Compositions Natural frequency Damping ratio Damping coefficient 1 Al+SiC(4%)+mica(1%) 232 0.01075 1.35 2 Al+SiC(4%)+mica(2%) 201 0.017 1.762 3 Al+SiC(4%)+mica(3%) 208 0.0215 2.33 Graph.1 shows compositions vs. damping coefficient The damping ratio, coefficient and other parameters are calculated using the values obtained from the free vibration test and a table containing the results of the test is made. From Table.1 we can see that the damping coefficient increases in each successive composition. The graphical representation in variation of damping coefficient for all three compositions clearly indicates that the value of damping coefficient increases with each composition. This is because in each successive composition the percentage of mica is increased. Vol. 5 Issue 2 March 2015 406 ISSN: 2278-621X International Journal of Latest Trends in Engineering and Technology (IJLTET) B. SEM Analysis – In order to know about the microstructure of the made aluminium silicon carbide mica composite Scanning Electron Microscope study is conducted. Before conducting the microstructure study, the surface of the specimen is to be cleaned and polished. The specimen is then etched using hydrogen fluoride (HF) just an hour before the SEM study. (a) (b) Figure.5 (a) Scanning electron microscope (b) etched specimen (a) Vol. 5 Issue 2 March 2015 (b) 407 ISSN: 2278-621X International Journal of Latest Trends in Engineering and Technology (IJLTET) Silicon carbide mica (c) Figure.6 (a) Al + SiC (4%) + mica (1%) (b) Al + SiC (4%) + mica (2%) (c) Al + SiC (4%) + mica (3%) The SEM analysis clearly shows the distribution of silicon carbide and mica particles in aluminium. It can be observed that the mica concentration has increased in each successive composition. IV. CONCLUSION It is observed that the aluminium metal matrix composites can be fabricated using stir casting method. It is subjected to free vibration test to evaluate the damping behavior and natural frequency of the composites. From the SEM photos it is clear that the reinforcements have been uniformly distributed in all the three compositions Thus it is proved that mica has an effect on vibrational property in aluminium metal matrix composites, such that increasing the mica content reduces the vibration of the material, thereby minimizing the energy loss and noise. REFERENCES [1] [2] [3] [4] [5] [6] [7] K. S. Uma Shankar, K. V. Gangadharan, Vijay Desai, B. Shivamurthy, ”Fabrication and Investigation of Damping Properties of Nano Particulate Composites” Journal of Minerals & Materials Characterization & Engineering. Lihua Liao, Xiuqing Zhang, Haowei Wang, Xianfeng Li, Naiheng Ma, “The characteristic of damping peak in Mg–9Al–Si Alloys”, Journal of Alloys and Compounds 429 (2007) 163–166. Hui Lu, Xianping Wang, Tao Zhang, Zhijun Cheng and Qianfeng Fang “Design, Fabrication, and Properties of High Damping Metal Matrix Composites—A Review “Materials 2009. Wu, G.H. Dou, Z.Y. Jiang, L.T. Cao, J.H. “Damping properties of aluminum matrix-fly ash composites”. Mater. Lett. 2006. Gowri Shankar M.C, Jayashree P.k, Raviraj Shetty, Achutha Kini, Sharma S.S, “Individual and Combined Effect of Reinforcements on Stir Cast Aluminium Metal Matrix Composites-A Review” International Journal of Current Engineering and Technology. Deonath, R. T. Bhat, P. K. Rohatgi, Preparation of cast aluminium alloy-mica particle composites, Science May 1980, Volume 15, Issue 5, pp 1241- 1251 Manoj Singla, D. Deepak Dwivedi1, Lakhvir Singh, Vikas Chawla, Development of Aluminium Based Silicon Carbide Particulate Metal Matrix Composite, Journal of Minerals and Materials Characterization and Engineering, vol.8, no.6 Vol. 5 Issue 2 March 2015 408 ISSN: 2278-621X
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