Advanced Materials Research Vols. 984-985 (2014) pp 546-550 Online available since 2014/Jul/16 at www.scientific.net © (2014) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.984-985.546
Worn Surface Analysis of Hybrid Metal Matrix Composite Umanath K1,a*., Selvamani S.T2,b., Palanikumar K3,c and Dinesh Ram G4,d 1,4
2
Mechanical Engineering, Vel Tech High Tech Dr.R.R. & Dr.S.R. Engineering College, Chennai, Tamilnadu, India
Mechanical Engineering, Vel Tech Multi Tech Dr.R.R. & Dr.S.R. Engineering College, Chennai, Tamilnadu, India 3
Mechanical Engineering, Sri Sairam Institute of Technology, Chennai-600044, India
a
[email protected],
[email protected],
[email protected], d
[email protected]
Keywords: Worm Surface, Scanning Electron Microscopy, hybrid Composite, Wear, Aluminium, Silicon Carbide, Aluminium oxide
Abstract. Metal to the metal wear analysis of Aluminium (Al6061grade) alloy, dis-continuously reinforced with ceramic particles of SiC and Al2O3 deliver this paper. The Al matrix with 5 to 25% of vol. Fractions of SiC and Al2O3 particulate reinforcements were formed in Hybrid Metal Matrix Composite (HMMC) by stirring casting technology. They are finding applications in automotive, aeronautical and sport goods. For the proper use of these composites, its mechanical properties and wear properties are to be evaluated. The dry sliding behavior of these SiC and Al2O3 particulates HMMCs and that of Al alloy at atmosphere was analyzed with a pin on disc type wear testing machine. The result indicates that, the scanning electron micrographs of the worn surfaces of the hybrid composites show the worn surface of the composite alloy is rougher than the unreinforced Al6061alloy.
Introduction Al metal matrix composites contain expected notice since of their high modulus, enhanced strength, and improved wear resistance more than usual Al metals. The discontinuously Reinforced particulate metal matrix composite is having higher strength compare with continuous particulate reinforced composites, the isotropic behavior and rate of discontinuous composites produce them potentially valuable good wear resistant materials [1]. Normally metal matrix Composite materials are widely useful for its quality of two or more reinforcement can be able to combine with no sincerely highlights their deficiency [2]. Al metal matrix composites contain arriving significant notice for applications in various industries like importantly aerospace industries for the reason that of their low density and high stiffness properties [3]. Al metal matrix composites have moreover been well thought-out because the replacement materials for advantages in the production of pistons, vehicle brake rotors and cylinder head, etc. A complete reconsiders of the present and prospective submission fore cast aluminium alloy composites in the automotive engineering field [4]. The amalgamation of non metals like SiC, Al2O3 etc., with an Aluminium alloy increases, its load carrying strength also increases. For this reason the load and transferred speed range are extremely high and its dry sliding wear behavior is gentle [5,6]. The dry Sliding wear behavior of
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the composites is important wherever there is relative motion between metal components. Many research works are completed to investigate the sliding wear properties of the aluminum matrix composite reinforced with different types of reinforcements such as SiC, Al2O3, TiC, TiB2 and graphite [7-9]. But a combination of two or more reinforcement compindly used in the previous research work is very less. The purpose of the current investigation work of the hybrid composite material was formed by the stir casting technique and the analysis of SEM test has been discussed. Experimental Work The metal to metal wear experiments are carryout in atmospheric conditions in a pin on disc type wear measuring apparatus with the help of ducom wear and friction monitor machine. The pins are loaded against the disc by a dead weight loading system. The pin specimens are flat ended pins of 8mm dia and 32 mm in long. The metal counterface disc is 100mm in diameter and 10mm in thickness. The pin slide on the disc at a radius of slide 50mm.The material of the counter disc is high quality hardened steel with hardness HV256. Before the wear test, each specimen is ground by 1µm alumina powder and the counter disc is ground by 2000 grit paper. Wear tests on composite specimens and unreinforced Al alloy are completed in dry metal to metal sliding condition under three different applied loads of 29.43N (3kgf), 39.24N (4kgf) and 49.05N (5kgf) for the various sliding distances of 945m, 1404m &1884m and Stable is sliding speeds of 1.050m/s for all samples. During the tests the relative humidity and temperature of the surrounding atmosphere is about 50% and 25ºC respectively. The test duration is 15 minutes at a stable sliding speed of 400rpm for all the tests. The upright altitude (displacement) of the composite work piece is incessantly calculated using a linear variable differential transformer (LVDT) of accuracy 1µm during the wear test and the height loss is in use as wear of the test work piece. A tentative result shows the weight loss in µm against sliding time in seconds (which is proportional to sliding distance) obtained from wear measuring apparatus.
Before test
V=1. 05m/s
Fig. 1 The photographs of the specimen before and after the wear test of various applied loads The specimens machined to the required size are presented and the photograph of the wear surface of the workpiece before the test and after the test is shown in Fig.1. All types of specimen, i.e., Al6061 alloy with reinforcement volume fractions of 2.5%SiCp+2.5% Al2O3p, 5%SiCp+5% Al2O3p, 7.5%SiCp+7.5% Al2O3p, 10%SiCp+10% Al2O3p, 12.5%SiCp+12.5% Al2O3p undergo a wear test under the following three load conditions. The various load conditions used for the wear tests are presented in Table I. The front sight of the pin on disc type wear testing instrument is presented in Fig.2 and the top view of the specimen rotating on the disc of the wear testing machine is presented in Fig.3.
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Table 1 Various load conditions used for the tests Test 1 2 3
Load applied Rotational speed of disc Time duration [N] [ rpm] [min] 29.43 39.24 49.05
Fig.2 Front view of Pin on disc type wear testing machine
400 400 400
15 15 15
Fig.3 Top view of the specimen rotating on the disc of the wear testing Machine
The wear of test specimens obtained from the height loss of the specimens for the period of processing the graphs is plotted with respect to work piece traveling distance in for three different applied loads 29.43N (3kgf), 39.24N (4kgf) and 49.05N (5kgf) is presented. In each figure, wear of unreinforced alloy and of five different composite specimens with varying volume percentage of particle reinforced (5 to 25%) are presented below. Results and Discussion Effect of Sliding Velocity of 1.05m/s. The various test results of the worn surfaces are discussed in details bellow. The typical graphical result of experimentally wear in µm from wear testing apparatus of different Vol. fraction reinforced of HMMCs at an applied load of 49.05N is shown in Fig. 4. It is indicated that the sliding distance is increasing the wear of the HMMC is increasing due to friction between the HSS plate and composite specimen. The high magnification SEM photograph of the worn area of various volume fractions reinforced HMMCs at the sliding distances of 945m at a load of 29.43N is presented. From this SEM photograph, it is observed that the wear area of the HMMCs is rougher than the Al alloy base metal. In HMMCs, cavities and bulky ridged regions are initiated on the wear area. The reality of the ceramic particulates is initiated within the cavities shows to a few particles are broken down and some of the particulates are pulled away as on the face. It is indicated a rough wear. SEM micrographs of magnification 20X of the worn areas of different Volume fractioned reinforcement HMMCs at the Sliding distances of 945m at a load of 29.43N is exposed in Fig. 5.
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(c) 15% Vol. fraction
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Fig.4 The typical graphical result of experimentally wear in µm from pin-on-disc type wear testing machine of 25% Vol. fraction reinforced of HMMCs at an applied load of 49.05N.
(d) 20% Vol. fraction
(a) 5% Vol. fraction
(e) 25% Vol. fraction Fig. 5 SEM micrographs of magnification 50X of different Vol. fraction reinforced HMMCs at a load of 29.43N.
(b) 10% Vol. fraction
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The examination of the wear area showed that the wear area of the HMMCs has been usually rougher than the base metal Al alloy. The result of hard particulates showing on the wear area and wobbly fragments among two areas. Because of the particulates oppose the delamination development, the wear resistance is supplementary in the case of HMMCs. Conclusions • The SEM photograph of the worn area of the HMMCs is usually much rougher, more than the base metal Aluminium alloy. • The worn area indicates a rough wear mechanism which is fundamentally an effect of hard particulate expose on the worn area. • The particulate opposes the delamination progression, the wear resistance is supplementary in the case of HMMCs. Acknowledgment The authors hope to be grateful Vel Dr. R. Rangarajan., Chancellor, Veltech Hightech Dr.R.R. and Dr.S.R. Engineering College, for the support and services provide for the preparation of this manuscript. References [1] Huei-Long Lee, Wun-Hwa Lu and Sammy Lap-IP Chan, Effect of aging on the sliding abrasive wear of P/M 2014 and 606 1 Al alloy-SiC particle composites, Materials Letters, 15(1992) 4952. [2] T.W. Cyne, and P.J. Withers, An Introduction to Metal matrix composites, Cambridge University, Cambridge (1993)78–82. [3] T.H. Sanders, and E.A. Starke, International Conference on Al–Lithium alloys, Materials & Composites Engineering Publications Ltd., Birmingham, UK (1989)1–40. [4] P. Rohatgi, Cast aluminum-matrix composites for automotive applications, Journal of Materials 43 (1991)10-15. [5] A.T. Alpas, and J. Zhang, Effect of microstructure (particulate size and volume fraction) and counter-face material on the sliding wear resistance of particulate-reinforced aluminum matrix composites, Metallurgical and Materials Transactions A 25 (5)(1994) 969 – 983. [6] A.P. Sannino and H. J. Rack, Dry Sliding Wear of Dis-continuously Reinforced Aluminium Composites: Review and Discussion, Wear 189 (1) (1995)1-19. [7] O. Yilmaz, and S. Butoz, Abrasive Wear of Al2O3 Reinforced Aluminium based Metal matrix composites, Composite Science and Technology 6 (2001) 2381–2392. [8] C.A. Caracostas, W.A. Chiou, M.E. Fine, and H.S. Cheng, Tribological Properties of Aluminium Alloy Matrix TiB2 Composite Prepared by In-Situ Processing, Metallurgical and Materials Transactions A 28 (2) (1997) 491–502. [9] S.C. Tjong, and K.C. Lau, Dry Sliding Wear of TiB2 Particle Reinforced Aluminium Alloy Composites, Material Science and Technology 16 (2000) 99–102.
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Worn Surface Analysis of Hybrid Metal Matrix Composite 10.4028/www.scientific.net/AMR.984-985.546 DOI References [7] O. Yilmaz, and S. Butoz, Abrasive Wear of Al2O3 Reinforced Aluminium based Metal matrix composites, Composite Science and Technology 6 (2001) 2381-2392. http://dx.doi.org/10.1016/S0266-3538(01)00131-2 [9] S.C. Tjong, and K.C. Lau, Dry Sliding Wear of TiB2 Particle Reinforced Aluminium Alloy Composites, Material Science and Technology 16 (2000) 99-102. http://dx.doi.org/10.1179/026708300773002717
