ITSEC International Journal of Engineering Sciences, Vol. 1, No. 1, January 2020, Greater Noida pp. 4-11

Fabrication and Characterization ofAluminum Matrix Composite

1Abhishek Kumar 2 Vivek Kumar Assistant Professor Assistant Professor Mechanical Engineering Department Mechanical Engineering Department IILM Academy of Higher Learning,Greater I.T.S. Engineering College, Greater Noida, Noida, Uttar Pradesh, Uttar Pradesh, India. [email protected] [email protected]

ABSTRACT higher cost of fabrication for high- Metal matrix composite materials performance MMCs, lower ductility and increasingly replace traditional materials toughness. Presently, MMCs tend to cluster used in building engineering, aeronautics, around two extreme types. One consists of mechanical engineering and in many other very high performance composites domains. It is related to a possibility of reinforced with expensive continuous fibers obtaining practically any combination of and requiring expensive processing beneficial properties of the material, e.g. methods. The other consists of relatively high vibration damping coefficient, high low-cost and low-performance composites abrasion resistance, and high value of the reinforced with relatively inexpensive Young’s modulus, low specific gravity and particulate or fibers. The cost of the first low coefficient of . In type is too high for any but military or space applications, whereas the cost/benefit the present investigation, Al 6351/Al2O3 metal matrix composite was fabricated by advantages of the second type over stir casting technique. Microstructure unreinforced metal alloys remain in characteristics wereobserved on doubt.The application of response surface metallurgical microscope to observe the methodology (RSM) and central composite distribution of reinforcement in matrix design (CCD) for modeling, optimization, alloy. Uniform distribution was observed and an analysis of the influences of in all samples. dominant machining parameters on thrust force, surface roughness and burr height in KEYWORDS: alloy the drilling of hybrid metal matrix (6351), Alumina (Al2O3). composites produced through stir casting route[1]. Many factors which influence the 1. INTRODUCTION effect of viscosity during Al–SiC MMC production. Processing periods (up to 65 Metal matrix composites (MMCs) usually min), stirring speeds (50–500 rpm), and consist of a low- metal, such as reinforcement sizes (13–100 µm) for two aluminum or , reinforced with different viscosity levels (1 and 300 mPa-s) particulate or fibers of a material, were investigated [2]. Particulate metal such as or . matrix composites (PMMCs) have attracted Compared with unreinforced , interest for application in numerous fields MMCs offer higher specific strength and [3]. The wear rate of spray formed stiffness, higher operating temperature, and composites is significantly lower than the greater wear resistance, as well as the base alloy and stir cast composite under opportunity to tailor these properties for a same sliding condition [4] .Comparing with particular application. However, MMCs the Newtonian case, the couple stress also have some disadvantages compared effects of fluids containing suspensions with metals. Chief among these are the

4 ITSEC International Journal of Engineering Sciences, Vol. 1, No. 1, January 2020, Greater Noida pp. 4-11

provide an enhancement in the load [8]. Rheological properties of aqueous capacity, as well as a reduction in the concentrated aluminium nitride (AlN) attitude angle and the parameter. suspensions have been investigated in the AA6063 aluminium matrix composite presence of a sintering aid, deffloculant, billets reinforced with SiC particles binder and plasticizers, in order to screen (Al/SiCp) were prepared by stir casting the most suitable experimental conditions method for process. The results to obtain a good rheological behavior for show that the die wear is affected tape casting thick and non-cracked tapes differently by the SiC particle with good flexibility[9].The wear rate of all size[5].Optical microscopy of the heat-treated specimens is less than that of conventional cast and stir cast the specimens in the as-cast condition. The hypereutectic alloy has shown that stir main reason for this improvement is clearly casting causes refinement of primary related to the hardness enhancement after silicon particles and modification of the aging treatment [10].The wear eutectic silicon compared to conventional resistance of the as-cast Al–Si alloy and cast alloy[6].The formation of TiB2 composites was decreased with increasing particles occurred via diffusion of sliding distance, while the wear resistance atoms through TiAl3 particles interface, of Al–Si alloy matrix composites has thereby reacting to form fine TiB2 particles increased with increasing wt% of Al2O3 [7].The use of aluminium-based particulate particles. This is due to higher load- reinforced MMCs for automotive carrying capacity of the hard reinforcement components and aircraft structures have Al2O3 particles, which limits the amount been shown to be highly advantageous over ofplastic deformation of the matrix their unreinforced alloys, due to their high [11].Literature survey did not reveal any specific strength and stiffness and superior systematic study of Al 6351/Al2O3metal wear resistance in a wide temperature matrix composites. Objective of the present range. SEM analyses of the fracture work Fabrication of Al 6351/Al2O3 metal surfaces of the tensile specimens showed matrix composites with different substantially similar morphologies for the percentage of reinforcement by stir carting as-cast and forged composites, both at method.Microstructure observation of all room and high temperature. The fabricated samples to observe distribution mechanism of damage was mainly of reinforcement. Investigation of decohesion at the matrix–particle interface mechanical properties of all samples.

2. EXPERIMENTATION corrosion resistance, Al 6351 offers extremely low maintenance. The MATRIX MATERIAL experimental results were found Most of the aerospace structures and its satisfactory to propose the alternative alloy allied infrastructure are made of aluminum for aircraft structures. The mechanical and alloy. In this context considering Al 6351 physical properties of aluminum alloy which was used for making pressure vessel (6351) have been reviewed from literature cylinders is now testing for aircraft data for the purpose of characterizing the structures. Al 6351 has high corrosion mechanical for manufacturing process in resistance and can be seen in forms of engineering application. Aluminum alloys extruded rod bar and wire and extruded are used in many applications in which the shapes. It is easily machinable and can combination of high strength and low have a wide variety of surface finishes. It weight is attractive in air frame in which also has good electrical and thermal the low weight can be significant value. Al 6351 is known for its light weight (density conductivities and is highly reflective to 3 heat and light. Due to the superior = 2.7g/cm ) and good corrosion resistance

5 ITSEC International Journal of Engineering Sciences, Vol. 1, No. 1, January 2020, Greater Noida pp. 4-11

to air, water, oils and many chemicals. times greater than steels. The chemical Thermal and electrical conductivity is four composition of alloy is follows

Table 1: Properties of aluminum alloy (Al 6351) [12]

aluminum Cu magnesium Silicon iron Manganese Others Remaining alloy Al 6351 0.1 0.4-1.2% 0.6-1.3% 0.6% 0.4-1.0% 0.3% Al %

It has higher strength amongst the 6000 structural alloy, in plate form. This alloy is series alloys. Alloy Al 6351 is known as a most commonly used for machining.

REINFORCEMENT MATERIAL toughness and ultimate tensile strength due to the presence of micro-sized Aluminum oxide (Al O ) is widely 2 3 reinforcement particles into the matrix. used as the reinforcement in the metal Generally, regards to the mechanical matrix composites.The mechanical and properties, the reinforcements result in physical properties of alumina (Al O ) have 2 3 higher strength and hardness, often at the been reviewed from literature data for the expense of some ductility. Aluminum- purpose of characterizing the mechanical matrix composites (AMCs) reinforced with properties of alumina for manufacturing particles and whiskers are widely used for process in engineering application. high performance applications such as in

automotive, military, aerospace and Table 2: Mechanical properties of (Al2O3) Alumina Grade pH Mesh electricity industries because of their (Al2O3) value size improved physical and mechanical Neutral(1344- Brockman 1 6.5- 100 properties. In the composites relatively soft 28-1) or 2 7.5 alloy like aluminum can be made highly resistant by introducing predominantly hard Metal–matrix composites (MMCs) are but brittle particles such as Al2O3 and SiC. most promising in achieving enhanced mechanical properties such as: hardness,

EXPERIMENTAL PROCEDURE mixed slowly in molten aluminium alloy with the help of stirrer. The material is left The materials used in the present work are for cool down in the crucible in which it aluminium alloy (Al 6351) and aluminium was melted and mixed.There are three samples in different ratios which are oxide (Al2O3 as reinforcement). These materials are chosen due to their easily prepared for testing mechanical properties. mixable property and gives good The ratios are shown below in the Table 3. mechanical properties. The aluminium Table 3: Composition selection alloy (Al 6351) is heated up to its melting Material Sample Sample Sample temperature 6000C in a mufflefurnace. 1 2 3 Temperature measurement is done with (Al 6351) 97.5% 95% 92.5% help of K-type thermocouple. (Al2O3) 2.5% 5.0% 7.5% Preheatedaluminium oxide at 1000Cis

6

ITSEC International Journal of Engineering Sciences, Vol. 1, No. 1, January 2020, Greater Noida pp. 4-11

Figure 1 a. Muffle furnace Figure 1 b. Preparation of sample by stir casting

Now the mixed composite after cooling and electrically driven machine which is used solidification is cut into desired shapes for to cut the hard composites. The MMC testing mechanical properties on the band samples prepared are shown in figures saw machine. The machine is an given below.

Figure 2: MMC (Al 6351+2.5% of Al2O3) Figure 3: MMC (Al 6351+ 5% of Al2O3)

Figure 4: MMC (Al 6351+7.5% of Al2O3)

7 ITSEC International Journal of Engineering Sciences, Vol. 1, No. 1, January 2020, Greater Noida pp. 4-11

Figure 5: MMC sample prepared for Figure 6: MMC sample for tensile test hardness test

Figure 7: MMC sample prepared for Figure 8: MMC sample prepared for toughness test microstructure

Grinding/polishing for a considerable time in order to get a smooth and clear surface of the samples. The cut samples prepared above had an uneven surface. So, the cut samples 3.RESULTS AND DISCUSSION were then taken for grinding/polishing Analysis of Microstructure operation. The sample was first held over a The microstructures of the MMC samples grinding machine with a moving belt to are seen using metallurgical microscope. obtain a smooth surface. The grinding was The term ‘microstructure’ in metal matrix done in such a way so that all the scratches composites is used to describe the are in the same direction and the grinded appearance of the reinforcement material. surface becomes flat. After this the samples Microstructure shows that the Al2O3 were polished using different grits of emery reinforcement distributed uniformly papers. Because the samples being throughout the casted component. Here aluminium alloy composites it is rubbed Al2O3 distribution did not show any over the emery paper for a small time. It segregation.Uniform distribution was was rubbed over an emery paper of 400, observed of all selected composition as 600, 800, 1000 grit and then over a very shown in figure 9. fine emery paper of 1200, 1600,2000 grit

8 ITSEC International Journal of Engineering Sciences, Vol. 1, No. 1, January 2020, Greater Noida pp. 4-11

X100 X100

Figure 9: (a) Al 6351+2.5 % Al2O3 reinforcement (b) Al 6351+5 %Al2O3 reinforcement

X100

(c) Al 6351+7.5 % Al2O3 reinforcement Analyses of Tensile Strength The specimens were tested according to Tensile tests are used to determine the ASTM E8M-01 standard. Specimens of sub elastic limit, elongation, tensile sized sample are length of 100 mm, width strength, yield strength and reduction in of 6 mm and gauge length is 36 mm.The area. Tensile tests were carried out at room ultimate tensile strength, percentage temperature using computerized universal elongation was calculated for each prepared testing machine with a capacity of 40 KN. sample. Table 4: Tensile Test of Al 6351+Al2O3 MMC

Samples Ultimate Elongation Break load Break True UTS Area

(of Al2O3) strength(N) (mm) (N) Elongation (N/ sq mm) (sq. mm) (mm) 2.5% 698.3 0.52 146.1 0.62 26 27.341 5.0% 642.5 0.51 209.9 0.69 21.4 24.453 7.5% 1531.1 2.42 1315 3.23 67.2 26

Analysis of Toughness Test initial energy of 300 J. According to ASTM E-23, standard specimen, sizes are 10 mm x In these MMC specimens toughness is 10 mm x 55 mm. for charpy impact test tested by breaking it with impact force of a analysis. The table shows the results while hammer weighing 21 kg. The Hammer is testing as follows: leaved from 140 degree of angle with the

9 ITSEC International Journal of Engineering Sciences, Vol. 1, No. 1, January 2020, Greater Noida pp. 4-11

Table 5: Toughness of Al6351+Al2O3 MMC

Trial Average Energy (Joule) Sample Composite Sample A B C No. Name (A+B+C) / 3

1 Al6351+2.5 % Al2O3 14 16 18 16.00

2 Al6351+5 % Al2O3 12 14 14 12.66

3 Al6351+7.5 % Al2O3 10 10 12 10.66

ANALYSIS OF HARDNESS TEST Al6351/2.5, 5, 7.5% wt. Al2O3 composite were prepared as per dimension (10 mm x The hardness test was carried on 10 mm x 25 mm) as ASTM E18-05, Rockwell Hardness testing method. For standard. hardness testing, the samples of

Figure 10: MMC sample after indentation on hardness testing machine. Table 6: Hardness of MMC

Rockwell Hardness at Sample Composite Sample Name (HRC) scale Mean Hardness No. Trial 1 Trial 2 Trial 3

1 Al6351+2.5 % Al2O3 42 45 51 46

2 Al6351+5 % Al2O3 50 51.5 53 51.5

3 Al6351+7.5 % Al2O3 57 58.4 60 58.4

10 ITSEC International Journal of Engineering Sciences, Vol. 1, No. 1, January 2020, Greater Noida pp. 4-11

CONCLUSION S.K. Chaudhury, A.K. Singh, C.S. Sivaramakrishnan, S.C. Panigrahi, “Wear The following conclusions are arrived and friction behavior of spray formed and based on the experimental investigation on stir cast Al–2Mg–11TiO2 composites”, the distribution of Al2O3 in themechanical Wear 258 (2005) 759–767. stir casting and its effect on mechanical [5] M. Baki Karma’s， Fehmi Nair, properties of the as cast MMCs at different “Effects of reinforcement particle size in weight fraction of Al2O3. MMCs on extrusion die wear”, Wear 265 1. In the present investigation, it was (2008) 1741–1750. observed that maximum mechanical [6] T.V.S. Reddy, D.K. Dwivedi, N.K.

properties were obtained for Al Jain, “Adhesive wear of stir cast 6351/7.5% Al2O3. hypereutectic Al–Si–Mg alloy under 2. The tensile strength of the as cast reciprocating sliding conditions”, Wear 266

composites increases on increasing (2009) 1–5. the weight fraction of Al2O3. [7] M. Emamy, M. Mahta, J. Rasizadeh, 3. The hardness of the MMCs is “Formation of TiB2 particles during higher than the unreinforced matrix dissolution of TiAl3 in Al–TiB2 metal metal and the hardness of the cast matrix composite using an in situ composites increases linearly with technique”, Composites Science and

increasing the weight fraction of Technology 66 (2006) 1063–1066. Al2O3. [8] L. Ceschini, G. Minak, A. Morri, 4. Microstructural observation “Forging of the AA2618/20 vol.% Al2O3p suggests that stirring action composite: Effects on microstructure and produces MMC with smaller grain tensile properties”, Composites Science and size and there is a good particulate Technology 69 (2009) 1783–1789. matrix interface bonding. [9] S.M. Olhero, J.M.F. Ferreira, 5. The increase in Al2O3 constituent “Rheological characterisation of water- toughness decreases with respect to based AlN slurries for the tape casting base metal. This is due to increase process”, Journal of Materials Processing in brittleness between the alloy Technology 169 (2005) 206–213. Al6351 and Al2O3 interfaces. [10] Karakulak Erdem, Zeren Muzaffer, 4.REFERENCES Yamanog˘l Ridvan, “Effect of heat [1] Thiagarajan Rajmohan, Kayaroganam treatment conditions on microstructure and Palanikumar, “Application of the central wear behaviour of Al4Cu2Ni2Mg alloy”, composite design in optimization of Trans Nonferrous Met Soc China 23:1898 machining parameters in drilling hybrid ((2013). metal matrix composites” , Measurement [11] Kala H, Mer KKS, Kumar S, “A 46 (2013) 1470–1481. review on mechanical and tribological [2] S. Naher , D. Brabazon , L. Looney, behaviors of stir cast aluminum matrix “Computational and experimental analysis composites”, Procedia Mater Sci 6:1951– of particulate distribution during Al–SiC 1960 (2014). MMC fabrication”, Composites: Part A [12] Mohanavel V., Rajan K., Senthil 38(2007) 719–729. Kumar K. R., “Study on mechanical [3] S.Tzamtzis , N.S. Barekar , N. Hari properties of AA6351 alloy reinforced with Babu , J. Patel , B.K. Dhindaw , Z. Fan, di-Boride (TiB2) composite by in “Processing of advanced Al/SiC particulate situ casting method”, Applied Mechanics metal matrix composites under intensive and Materials 787 (2015) 583-587. [4] shearing – A novel Rheo-process”, Composites: Part A 40 (2009) 144–151.

11 ITSEC International Journal of Engineering Sciences, Vol. 1, No. 1, January 2020, Greater Noida pp. 4-11