Characteristic Study and Enhancement of Mechanical Properties of Al2024 Gray Cast Iron Powder Reinforced MMC by Heat Treatment

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1 ISSN: X Impact factor: (Volume2, Issue6) Available online at: Characteristic Study and Enhancement of Mechanical Properties of Al2024 Gray Cast Iron Powder Reinforced MMC by Heat Treatment Manikanta M 1, S. S. Sharma 2, Sathish Rao U 3 1 Post Graduate Student, 2 Professor, 3 Associate Proffesor (manikanta0904@gmail.com) (ss.sharma@manipal.edu) (sathish.raou@manipal.edu) Department Of Mechanical & Manufacturing Engineering, Manipal Institute Of Technology, Manipal, Karnataka , India Abstract. It is proposed to study the mechanical properties of Al2024-gray cast iron composite with age hardening process and compared with as cast specimen. All heat treatment processes are carried out in atmospheric conditions. Al2024 is a reasonable choice as a matrix material to prepare MMCs owing to high strength (especially at elevated temperatures), toughness, and, in specific cases weldability. Among different types of the recently formed composite materials, particle reinforced MMC and in particular aluminium as matrix material has found to have industrial applications. Gray cast iron powder reinforced aluminium 2024 composites possess a unique combination of high specific strength, high elastic modulus than the corresponding nonreinforced matrix alloy system. By double stir casting method, Al2024 will be reinforced with gray cast iron powder. Heat treatment is given so as to tailor and improve the required mechanical properties as per the requirement. Gray cast iron is selected since it is believed to improve the hardness as well as the machinability due to the presence of both iron carbide and free graphite in gray cast iron powder. Here three different proportion of gray cast iron composite are prepared by stir casting process. Age Hardening treatment is given to the samples with different percentage of gray C.I, and different properties such as microstructure, hardness and corrosion are compared with as cast Al2024- gray cast iron composite of respective composition. The possible outcomes maybe increase in mechanical properties by addition of gray cast iron. Keywords: Al2024 Grey Cast Iron, Stir Casting, Age Hardening, MMC. I. Introduction Conventional materials have limitations with respect to achievable combinations of strength, stiffness and density. In order to overcome this, metal matrix composites have been fabricated. The MMC has two main components namely matrix and reinforcement. The reinforcement chosen is usually a light weight material (such as aluminium, magnesium and titanium) with good strength to 2016, IJARIIT All Rights Reserved Page 1

2 weight ratio. The reinforcement for these materials is usually ceramics, since they give good combination of stiffness, strength and density. The reinforcement materials are usually SiC, Al 2 O 3, B 4 C, TiC, TiB 2, graphite. Aluminium and its alloys have a large range of capability and applications which make it the material for the number of products in the market. The 2xxx series can be heat treated and has high strength (especially at high temperature), toughness and in some cases weldability. They cannot resist atmospheric corrosion, so are usually painted or claded in such conditions. Aluminium 2024 has good machinability, higher strength and fatigue resistance than the other members of 2xxx series like 2014 and One of the main drawbacks of this material is that they have poor tribological properties, hence it has to be engineered in such a way that it improves tribological properties without compromising much on the strength to weight ratio. The MMC must have good machinability along with high strength to weight ratio, hence graphite powder is added during the fabrication process which acts as self-lubricant. Many research works have been carried out in order to increase the machinability which includes addition of graphite, fly ash etc. Also, more than one reinforcement has been introduced into the matrix in order to tailor the properties to the desired value. II. Experimental Details The table 1 gives the composition of the base material Al2024. Particle size of the reinforcement Gray cast iron is 55-70µm. Composites with different weight percentage of the reinforcement material were successfully cast. Table 1: Chemical Composition of Al2024 in wt% Elements Cu Mg Mn Fe Cr Si Zn Al Percentage Bal. The fabrication of the composites was carried out in liquid metallurgy route via step stir casting technique. The Aluminium 2024 T3511 is purchased from Perfect Metal Works Bangalore. The gray cast iron pieces are collected from workshop, it is preheated t C. After complete melting, Hexacachloro ethane(c2cl6) was introduced through a graphite rod for degassing of trapped gases in the melt. The impurities i.e. in the form of slag were skimmed out. After effective degassing and slag removal, grey cast iron powder of purified scrap of particulat C for 1hr was introduced into the vortex of the molten metal after the attachment of the stirrer. The stirrer was set to the desired rpm for the formation C for better solubility of Gray cast iron powder in the m C. Two different weight percentage of grey cast iron powder were added and resulting specimen with 2%, 4% and 6% by weight percentage of grey cast iron powder were obtained. 2.1 Age Hardening of the samples The cast Specimens were first Homogenized at C for 8hrs in Muffle furnace. Homogenizing allows better distribution of solute atoms in the base metal and achieves homogeneous chemical composition. The specimens are treated precipitation hardening treatment with solutionizing as first step in the process and aged. This was carried out in Muffle furnace at C for 2hrs. The specimens were then quenched in a water bath and then aging treatment was carried out in Hot Air Oven at two different temperatures i.e. at C and C. 2.2 Hardness Test Micro Vickers hardness test was conducted to test the hardness of the specimen for age hardening. Micro Vickers hardness machine keeping load of 100kgf was used and hardness was recorded. 2016, IJARIIT All Rights Reserved Page 2

3 2.3 Tensile test Tensometer with load cell value kept at 20.5KN, test mode as break, length increment value as 0.01mm and with the cross head speed of 3mm/min is used to perform tensile test.. The load vs deformation graph was then obtained and ultimate tensile strength of specimens was plotted in a graph. III. Results and Discussion The results of all the tests conducted are recorded in the form of tables and graphs. For microstructure analysis the microphotographs are taken to analyze the distribution of reinforcements in Al2024-Grey cast iron composite. Hardness test and charpy impact strength test is carried out to study the effect of reinforcement. Tensile test is conducted to find out the ultimate tensile strength of the composite material. The results are discussed with proper explanation in each case and finally concluded based on the results obtained. 3.1 Hardness test result Precipitation hardening treatment was carried out and hardness was found at different time intervals. The specimens were solutionized first in the muffle furnace for 2hrs at C and then immediately water quenched at room temperature then the specimens were transferred into the hot air oven and for regular interval of time the specimens were checked for hardness i.e. Vickers hardness number (VHN) was noted. Accordingly the aging curves were plotted. Fig.1: Variation of hardness w.r.t aging time for different temperatures 0% Gray C.I composite Fig.2: Variation of hardness w.r.t aging time for different temperatures in 2% Gray C.I composite 2016, IJARIIT All Rights Reserved Page 3

4 VICKER'S HARDNESS(HV M Manikanta et al., International Journal of Advance Research, Ideas and Innovations in Technology. Fig.2: Variation of hardness w.r.t aging time for different temperatures in 4% Gray C.I composite Fig.4: Variation of hardness w.r.t aging time for different temperatures in 6% Gray C.I composite % C.I 2% C.I 4% C.I 6% C.I As cast Aged 100⁰C Aged 200⁰C Fig.3: Comparison of peak hardness with variation in temperature for 0%,2%,4%,6% composites. 3.2 Tensile test The ultimate tensile strength of as cast and age hardened specimens is plotted in the graph as shown below. 2016, IJARIIT All Rights Reserved Page 1

5 ULTIMATE TENSILE STRENGTH(MPa) M Manikanta et al., International Journal of Advance Research, Ideas and Innovations in Technology % C.I 2% C.I 4% C.I 6% CI As bought Aged 100⁰C Aged 200⁰C Conclusion This study reveals that artificial aging presented a positive effect on hardness properties of both the composites. When evaluating the precipitation hardening of composites, this study identifies its hardness behavior in two different aging temperatures with time. This analysis led to the conclusion that optimum aging could be achieved at 100 C. It is also observed that as the weight percentage of Gray C.I increases the hardness of the composite in peak aged condition. The peak hardness of the 6% Gray C.I composite is found to be the maximum when compared to others. The tensile test result showed that 4% Gray C.I composite in peak aged condition at 100⁰C has the highest ultimate tensile strength. There is increase in tensile strength for both as cast and peak aged specimens (both 100⁰C and 200⁰C) from 0% to 4% and then decreases for 6% of reinforcement. References 1. Rebba, Bhargavi, and N. Ramanaiah. "Studies on Mechanical Properties of 2024 Al-B4C Composites." Advanced Materials Manufacturing & Characterization 4, no. 1 (2014): Boopathi, M. Mahendra, K. P. Arulshri, and N. Iyandurai. "Evaluation of mechanical properties of aluminium alloy 2024 reinforced with silicon carbide and fly ash hybrid metal matrix composites." American Journal of Applied Sciences 10, no. 3 (2013): Sameezadeh, M., M. Emamy, and H. Farhangi. "Effects of particulate reinforcement and heat treatment on the hardness and wear properties of AA 2024-MoSi 2 nanocomposites." Materials & Design 32, no. 4 (2011): Rebba, Bhargavi, and N. Ramanaiah. "Evaluation of Mechanical Properties of Aluminium Alloy (Al-2024) Reinforced with Molybdenum Disulphide (MOS 2) Metal Matrix Composites." Procedia Materials Science 6 (2014): Surappa, M. K. "Aluminium matrix composites: Challenges and opportunities." Sadhana 28, no. 1-2 (2003): Sharma, Pardeep, Gulshan Chauhan, and Neeraj Sharma. "Production of AMC by stir casting an overview." International Journal of Contemporary Practices 2, no. 1 (2011): Singla, Manoj, D. Deepak Dwivedi, Lakhvir Singh, and Vikas Chawla. "Development of aluminium based silicon carbide particulate metal matrix composite." Journal of Minerals and Materials Characterization and Engineering 8, no. 06 (2009): Mathur, Shubham, and Alok Barnawal. "Effect of Process Parameter of Stir Casting on Metal Matrix Composites." International Journal of Science and Research (IJSR) 2, no. 12 (2013): Pa, Vivekanandan. "The Experimental Analysis of Stir Casting Method on Aluminium-Fly Ash Composites." (2013). 10. Kerti, Isil, and Fatih Toptan. "Microstructural variations in cast B 4 C-reinforced aluminium matrix composites (AMCs)." Materials Letters 62, no. 8 (2008): , IJARIIT All Rights Reserved Page 2

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