OPTIMIZATION OF EDM PROCESS PARAMETERS ON HYBRID COMPOSITE WITH ONE FACTOR APPROACH

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 5, May 2017, pp , Article ID: IJMET_08_05_062 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed OPTIMIZATION OF EDM PROCESS PARAMETERS ON HYBRID COMPOSITE WITH ONE FACTOR APPROACH MurahariKolli, ShaikKhadarBasha Mechanical Engineering Department, K L University, Andhra Pradesh, India. MadhuSudhan Rao.D, Ramapulla Reddy N, K.V. Manoj, K. Sai Krishna, K.N.S.Abhishek Undergraduate Student, Mechanical Engineering Department, K L University, Andhra Pradesh, India. ABSTRACT Aluminium hybrid composites are widely used in various industries because of high strength, low weight ratio, low thermal expansion, high specific stiffness and good wear resistance. Present investigation is carried out on the EDM process parameters on Aluminium Hybrid Matrix Composite (AHMC). One factor at time approach was considered for conducting the experiments. Initial studies are carried out on the reinforcement particles effect on the AHMC to find the mechanical properties with boron carbide (B 4 C) and graphite (Gr) particles. Aluminium 7075 alloy is used as the matrix material with reinforcement of B 4 C particles from 4 to 12 wt% in steps of 4 wt% and fixed quantity of 3 wt% of graphite. The hybrid composites were fabricated by stir casting technique. The hardness and tensile properties were studied on the prepared composites. Furthermore, EDM studies are carried out on the AHMC. The considered input parameters current, pulse on time and pulse off time on their selected output parameters like material removal rate (MRR), surface roughness (Ra) and tool wear rate (TWR). Key words: Aluminium, Low weight ratio, Aluminium Hybrid Matrix Composite. Cite this Article: MurahariKolli, ShaikKhadarBasha, MadhuSudhan Rao.D, Ramapulla Reddy N, K.V. Manoj, K. Sai Krishna and K.N.S.Abhishek Optimization of EDM Process Parameters on Hybrid Composite with One Factor Approach. International Journal of Mechanical Engineering and Technology, 8(5), 2017, pp INTRODUCTION Vital applications in engineering field require alloys & materials with broad range of properties like high stiffness, weight ratio, high impact strength which is rarely possible in editor@iaeme.com

2 MurahariKolli, ShaikKhadarBasha, MadhuSudhan Rao.D, Ramapulla Reddy N, K.V. Manoj, K. Sai Krishna and K.N.S.Abhishek monolithic material systems so, hence we adapt for more newer MMC in engineering applications.mmc in now a days are being used in aerospace and automobile industries owning to their improved properties such as elastic modulus, hardness, tensile strength at even very intense temperatures{2,6}.most commonly used metallic matrices include AL,MG,TI,CU and their alloys. These reinforcements are mostly used as particulates. The property of particulate-reinforced composites over others is their ability to undergo plastic deformation without being damaged with cost effective advantage is highly recommended. Aluminum is considered as one of the most predominant matrix material considering its combined properties of ductility and toughness of the soft matrix material and strength, hardness and modulus of hard reinforcement material[1].for MMCs B 4 C,SiC,Al2O3 and Gr are the most common preferred particulate reinforcements. Abrasion resistance is greatly improved due to ceramic particulate reinforced composite[2]. 2.OBJECTIVES OF THE PROJECT The objective of this research work is to develop AL7074/ B4C /Gr particulate hybrid metal matrix composite with superior mechanical properties. Specimens with different weight percentages are prepared by stir casting. Test specimens are prepared according to ASTM standards. 3.EXPERIMENTAL DETAILS 3.1. Material Selection Matrix Material Heat treated aluminum alloy AL7075 is chosen as matrix material due to its wide usage in engineering sector. Aluminum7075 is an aluminum alloy with major alloying element as zinc. The composition of Al7075 is shown in the table 1. Table 1 Composition of Al7075 Material Zn Mg Cu Si Mn Fe Cr Ti Al Weight Remaining MECHANICAL PROPERTIES OF AL7075 The mechanical properties of Al7075 are shown in the Table 2 Table 2 Mechnical Properties of Al 7075 Mechanical properties Ultimate Tensile strength 572Mpa Yield strength 95Mpa Hardness(vickers) 175 Elongation at break 11% Melting point C Density 2.81 g/cm3 Value editor@iaeme.com

3 Optimization of EDM Process Parameters on Hybrid Composite with One Factor Approach Reinforcement Materials Boron carbide and graphite particulates of 44 microns are used as reinforcement material. Wt.% of gr is maintained constant. Following table shows the properties of boron carbide and graphite powders. Table 3 Properties of boron Carbide and Graphite Powders Property B 4 C Gr Melting Point 0 C Hardness MPa mohs scale Density g/cm Fracture toughness MPa/m Poisson s Ratio Fabrication of AL7075-B 4 C-Gr Composite In the fabrication of AL7075 hybrid metal matrix composite (Al7075+ B 4 C+Gr) stir casting technique is used.al7075 is the matrix material, boron carbide and graphite are reinforcing particles. About 1.2kg of pure Al7075 was melted in the silicon carbide crucible at C.44 microns sized particles of boron carbide and graphite were pre-heated and introduced into the cricible os molten alloy. the molten alloy was then stirred with a mechanical stirrer made of graphite for a duration of 10mins. the stirrer is maintained at a speed of 700rpm. the molten metal combined with reenforcements is poured into a cast iron mould and was left in air to cool down to room temperature. Table 4 Composition used for Metal Matrix Composite Sample No. Amount of Al-7075(gm) Amount of B 4 C (gm) Amount of Gr(gm) Sample 1(4% B 4 C & 3%Gr) Sample 2(8% B 4 C & 3%Gr) Sample 3(12% B 4 C &3%Gr) METAL (AL-7075) Reinforcement materials (B 4 C and Gr) C C MELTING PREHEATING STIRRING Hybrid composite HYBRID METAL MATRIX Figure 1 Flow chart for composite preperation editor@iaeme.com

4 MurahariKolli, ShaikKhadarBasha, MadhuSudhan Rao.D, Ramapulla Reddy N, K.V. Manoj, K. Sai Krishna and K.N.S.Abhishek 3.3. Mechanical Testing All the mechanical testing procedures are conducted at ambient temperature. Vickers hardness testing machine is used for performing hardness testing. All the tests are conducted as per ASTM standard. The repeated for three incidents for each specimen and averagevalues are noted. Tensile tests were carried out with universal testing machine(utm). 4.RESULTS AND DISCUSSIONS 4.1. Hardness It is observed that there is increase in hardness of the sample with the increase in B 4 C.The increase is plotted in fig.2. boron carbide particles act as a load bearing elements in hybrid composites,thus enhances mechanical property of the material. Brinells hardness(bhn) Wt% of B 4 C Figure 2 Brinells Hardness 4.2. Ultimate Tensile Strength Structural strength of the composite is significantly effected by the addition of reinforcemets to the metal matrix.it is observed that increase in the B 4 C particles leads to increase in the tensile strength of the hybrid composite material. Fig.3 shows the tensile strength of the samples. Tensile Strength Wt % of B 4 C Figure 3 Tensile strength editor@iaeme.com

5 Optimization of EDM Process Parameters on Hybrid Composite with One Factor Approach (1) (2) Figure 4 Sample after tensile test % elongation Wt% of B 4 C Figure 5 variation of elongation Figure 5 shows the variation of elongation with respect to wt. % of B 4 C. With increase in B 4 C particles there is a decrease in the percentage elongation of the composite. Figure 6 sample after elongation 5. IMPACT TEST(CHARPY IMPACT 'V' NOTCH) Test procedure(is ) is followed according to the Bureau of Indian Standards (BIS).Results are shown in fig editor@iaeme.com

6 MurahariKolli, ShaikKhadarBasha, MadhuSudhan Rao.D, Ramapulla Reddy N, K.V. Manoj, K. Sai Krishna and K.N.S.Abhishek AL7075/4% B4C/3% GRAPHITE AL7075/8% B4C/3% GRAPHITE AL7075/12% B4C/3% GRAPHITE Figure 7 Impact test results Figure 8 Before test Figure 9 After test 6.CHEMICAL COMPOSITION Table 5 Chemical composition (Al %-B 4 C +3%-Graphite) Material Identification Al %- B 4 C +3%- Graphite Si Fe Cu Mn Mg Cr Zn Ti Al REM Table 6 chemical composition (Al %-B 4 C +3%-Graphite) Material Identification Al %- B 4 C +3%- Graphite Si Fe Cu Mn Mg Cr Zn Ti Al REM editor@iaeme.com

7 Optimization of EDM Process Parameters on Hybrid Composite with One Factor Approach Table 7 chemical composition (Al %-B 4 C +3%-Graphite) Material Identification Al %- B 4 C +3%- Graphite Si Fe Cu Mn Mg Cr Zn Ti Al REM Figure 10 Chemical composition sample 1 Figure 11 chemical composition sample 2 7. EDM STUDIES ON AL HYBRID COMPOSITE 7.1. Effect on the current The experiments are done by varying current keeping all other process parameters constant to know the output responses such as MRR and SR, TWR. Current was varied from 2A to 10A and all other input parameters considered are Ton=35, Toff=15 and voltage =40. The effect of output responses is mentioned in the table 8. Table 8 Results of MRR, Ra and TWR varying the current S.no Current(A) MRR(mm 3 /min) Ra(µm) TWR(mm 3 /min) Effect on the Pulse on time In these experiments, Ton was varied from 15µs to 35µs and all other input parameters current=10a, Toff=15, voltage=40 are kept constant. The effect of output response like MRR, Ra and TWR are varied due to change in Pulse-on time are given in the Table 9. Table 9 Results of MRR, SR and TWR varying the pulse-on time S.no Pulse on time (µs) MRR(mm 3 /min) Ra (µm) TWR(mm 3 /min) editor@iaeme.com

8 MurahariKolli, ShaikKhadarBasha, MadhuSudhan Rao.D, Ramapulla Reddy N, K.V. Manoj, K. Sai Krishna and K.N.S.Abhishek 7.3. Effect on the Pulse off time In these experiments, T-off was varied from 15µs to 35µs and all other input parameters current=10a, Ton=35, Gap voltage=40 are kept constant. The output response like MRR, Ra and TWR are changing due to change in Pulse-on time are given in the Table 10 S.no Table 10 Results of MRR, Ra and TWR varying the Pulse off time (Toff) Pulse off time(µs) MRR(mm 3 /min) Ra(µm) TWR (mm 3 /min) Influence of the process parameters on MRR Figure 12(a) shows the influence of current on MRR. It depicts that the current is increase with increase in the value of MRR. High amount of material is removed with the increase in current results in increase of MRR. Low amount of MRR is obtained at initial stage of current as current intensity is low. Fig. 12(b) shows the influence of Pulse on time on MRR. It shows that the pulse on time is increase with MRR also increases at initial conditions. At high value of pulse on time more amount of material is heated and melted but not removed from the machining surface. Fig.12(c)reveals that pulse off time is increase but MRR is decreases. Figure 12(a) Current Vs MRR Figure 12(b) Pulse on time Vs MRR Figure 12(c) Pulse off time Vs MRR editor@iaeme.com

9 Optimization of EDM Process Parameters on Hybrid Composite with One Factor Approach 7.5. Influence of the process parameters on SR The influence of current vs Surface roughness is shown in the Figure 13(a). The Figure indicated that when current is increased surface roughness is increases. The influence of pulse-on time vs. Ra is shown in the Figure 13(b). The Figure reveals that pulse-on time is increases SR is increased at certain conditions. After that pulse-on time is increased decreasing the Ra because of less amount of material is removed. Fig 13(c) reveals that pulse off time is increasing the surface roughness is decreasing. Figure 13(a) SR Vs Current Figure 13(b) Ra vs. Pulse- on time Figure 13(a) SR Vs pulse off time 7.6. Influence of the process parameters on TWR Figure 14(a). reveals that the influence of current vs TWR. The TWR is increased with increase in current. When high current is passed through the electrode more discharge energy is supplied and that effects in the increase of TWR. 14(b).The Figure reveals that pulse on time is increases TWR is slightly increased at certain conditions. Fig 14(c) reveals that pulse off time is increasing the TWR is increasing Figure 14(a) TWR Vs Current Figure 14(b) TWR Vs Pulse on time

10 MurahariKolli, ShaikKhadarBasha, MadhuSudhan Rao.D, Ramapulla Reddy N, K.V. Manoj, K. Sai Krishna and K.N.S.Abhishek Figure 14(c) TWRVs Pulse off Time 8. CONCLUSION For the fabrication of AL 7075-B 4 C-Gr hybrid composite by using stir casting methos enables the proper districbution of reinforcement particles. From the experimental investigation of the following conclusions were drawn on the mechanical properties of the B 4 Cand graphite reinforced Al 7075 hybrid composite. REFERENCES With the increase in the percentage of B 4 C particles on the metal matrix,there is a significate incresese in the hardness.maximum hardness is obtained for 12% of B 4 C and 3% graphite. The Ultimate tensile strength increased with an increase in wt% of reinforcement in the Hybrid composite. The addition of reinforcements of Al7075 lead to decrease in malleability of material. The MRR is increased with increase in the discharge current and pulse-on time. The lower surface roughness is obtained at initial conditions of discharge current and pulse-on time When a high current is passed through the electrode high discharge energy is supplied due to this effects increase in the TWR. [1] R.keshavamurthy,Sadananda Mageri,Ganesh Raj, "Microstructure and Mechancial Properties Of Al7075-Tib 2 In-Situ Composite",Vol. 1(10), 6-10, ISSN [2] G.B. VeereshKumar,C.S.P. Rao, N.Selvaraj, "Mechanical And Tribological Behavior of Particulate Aluminum Metal Matrix Composites", journal of minerals & characterization &engineering, Vol. 10, No.1, pp.59-91, [3] JithinJose, Dr.P.Muthu,"Studies on Mechanical And Wear Properties of Al7075/Zircon/Flyash Hybrid Metal Matrix Composites" (ICCREST), E-ISSN : ) ShaikKhadarBasha, M.V.JagannadhaRaju, MurahariKolli Experimental Study of Electrical Discharge Machining of In conel X-750 Using Tungsten-Copper Electrode, (ICMMM). [4] Mane S.G. and Hargude N.V, Parametric Optimization of Near Dry Electrical Discharge Machining Process For Aisi Sae D-2 Tool Steel International Journal of Mechanical Engineering & Technology (IJMET), Volume 6, Issue 1, 2015, pp , ISSN Print: , ISSN Online: [5] Z. Ahmed and D. K. Mahanta, A Comparative Study on Material Removal Rate by Experimental Method and Finite Element Modelling In Electrical Discharge Machining International Journal of Mechanical Engineering & Technology (IJMET), Volume 4, Issue 5, 2013, pp , ISSN Print: , ISSN Online: editor@iaeme.com