Scholarly article on topic 'Effects of PCD and Uncoated Tungsten Carbide Inserts in Turning of In-situ Al6061-TiC Metal Matrix Composite'

Effects of PCD and Uncoated Tungsten Carbide Inserts in Turning of In-situ Al6061-TiC Metal Matrix Composite Academic research paper on "Materials engineering"

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{In-situ / "halide salts" / turning / "cutting force" / "surface roughness ;"}

Abstract of research paper on Materials engineering, author of scientific article — D. Sai Chaitanya Kishore, K. Prahlada Rao, A. Mahamani

Abstract In the present investigation Al6061-TiC with 2 wt% TiC, 4 wt% TiC is produced by in-situ technique, SEM and EDX are performed on the fabricated composite for to know the presence of TiC reinforcement. The fabricated composite rod is subjected to turning experiments in dry environment for to find out the cutting force and surface roughness. The experiments are performed at five different ranges of cutting speed, feed rate and depth of cut by using PCD and uncoated tungsten carbide insert. From the experimental results it was find out that cutting force and surface roughness were decreasing with increase in cutting speed and increasing with the increase in feed rate and depth of cut. The experimental results also shows that the values of cutting force and surface roughness are increased by using uncoated tungsten carbide insert than that of PCD insert.

Academic research paper on topic "Effects of PCD and Uncoated Tungsten Carbide Inserts in Turning of In-situ Al6061-TiC Metal Matrix Composite"

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Procedía Materials Science 5 (2014) 1574 - 1583

International Conference on Advances in Manufacturing and Materials Engineering,

AMME 2014

Effects of PCD and uncoated tungsten carbide inserts in turning of in-situ A16061-TiC metal matrix composite

D. Sai Chaitanya Kishorea' * K. Prahlada Raob, A. Mahamanic

aDepartment of Mechanical Engineering, Chiranjeevi Reddy Institute of Engineering & Technology, Anantapur, Andhra Pradesh, India.

bDepartment of Mechanical Engineering, Jawaharlal Nehru Technological University, Anantapur, Andhra Pradesh, India. cDepartment of Mechanical Engineering, Sri Venkateswara College of Engineering and Technology, Chittoor, Andhra Pradesh, India.

Abstract

In the present investigation A16061-TiC with 2 wt% TiC, 4 wt% TiC is produced by in-situ technique, SEM and EDX are performed on the fabricated composite for to know the presence of TiC reinforcement. The fabricated composite rod is subjected to turning experiments in dry environment for to find out the cutting force and surface roughness. The experiments are performed at five different ranges of cutting speed, feed rate and depth of cut by using PCD and uncoated tungsten carbide insert. From the experimental results it was find out that cutting force and surface roughness were decreasing with increase in cutting speed and increasing with the increase in feed rate and depth of cut. The experimental results also shows that the values of cutting force and surface roughness are increased by using uncoated tungsten carbide insert than that of PCD insert.

© 2014 Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.Org/licenses/by-nc-nd/3.0/).

Selection and peer-review under responsibility of Organizing Committee of AMME 2014

Keywords: In-situ;halide salts;turning;cutting force;surface roughness;

1. Introduction

In recent years composite materials are mostly used in different industrial applications like aerospace, automobile and marine. Composite materials have properties like high strength, stiffness, hardness, fatigue and wear resistance.

* Corresponding author. Tel.: +91-9959545688 E-mail address: dskishore66@gmail.com

2211-8128 © 2014 Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Selection and peer-review under responsibility of Organizing Committee of AMME 2014 doi: 10.1016/j.mspro.2014.07.345

Aluminium is mostly used as matrix material due to its light weight and ceramic materials are used as reinforcement for to improve hardness and other properties. Sai et al. (2013) stated that B, C, A1203, TiB2, BiC and TiC e.t.c are used as reinforcement material in particle form. Kaczmar et al. (2000) mentioned that metal matrix composites are produced by stir casting, squeeze casting, spray deposition, liquid infiltration, and powder metallurgy and stir casting process is most economical among all the process. According to Mahamani et al. (2011) metal matrix composites produced by ex-situ process suffers thermodynamic instability between matrix and reinforcements, restricts their ambient and high temperature mechanical properties. In in-situ process the reinforcement is developed within the matrix by the reaction of halide salts with the molten aluminium. Daniel et al. (1997) stated that reinforcement formation in in-situ process provides greater control of size and level of reinforcements, as well as the matrix reinforcement interface, yielding better tailorability of the composites. According to Mahamani et al. (2011) in-situ composites are having advantages like they are more homogeneous in their micro structure and thermodynamically more stable and they also have strong interfacial bonding between the reinforcements and the matrix. Lewis (1991) stated that in-situ composites are mostly used in development of wear parts for pumps, valves, chute liners, jet mill nozzles, heat exchangers, gun barrel liners. Addition of TiC reinforcement to the aluminium matrix will maintain the better mechanical properties even at high temperatures. Birol (2008) investigated that TiC particles form in increasing number by increase in reaction temperature and it also decreases the reinforcement size. Yucel (2008) identified that A13Ti particles help to clean the surface oxides of the aluminium powders and play a key role in the liquid phase sintering process. Kalaiselvan et al. (2011) produced A1-B4C composites by modified stir cast process and identified that micro and macro hardness of the composites were increased with the addition of B4C particles. Anand et al. (2012) fabricated Al-4.5%Cu/10%TiC metal matrix composite and found that the tensile strength, fracture surface and hardness were improved by adding TiC reinforcement. Jerome et al. (2010) performed wear tests on in-situ Al-TiC composites and found that there is decrease in wear rate with the increase in reinforcing phase. Anandakrishnan et al. (2011) performed machinability study on Al-6061-TiB2 and found that high speed causes rapid tool wear due to generation of high temperature in the machining interface. Ram et al. (2006) analyzed cutting forces during the shaping operation and found that cutting force was less as compared to pure aluminium. Senthil et al. (2013) did turning investigation on Al-Cu/ TiB2 and found that BUE formation is more in the Al-Cu/ TiB2 than that of the base alloy. Pradeep et al. (2013) studied the influences of machining parameters on Al-4.5Cu-TiC, in which TiC reinforcement was produced by the reaction of activated charcoal with titanium. There was less work was carried in machining of in-situ Al-TiC composite and no work is carried on the comparative study of the two different inserts in the machining of A16061-TiC composite produced by the reaction of K2TiF6 and graphite powder with the molten aluminum. In the present research A16061-2%TiC and A16061-4%TiC metal matrix composites were fabricated by In-situ process. Micro hardness tests were performed for to know the improvement in hardness of the fabricated A16061-TiC composite. SEM and EDX tests were performed for to know the arrangement and presence of TiC particles. Turning experiments were performed on the A16061-0%TiC, A16061-2%TiC and A16061-4%TiC by using PCD and results of the A16061-0%TiC and A16061-4%TiC compared for both the PCD and uncoated tungsten carbide insert for to evaluate the response cutting force and surface roughness.

2. Experimental work

2.1. Fabrication and characterization of in-situ A!6061-TiCMMC

Al-6061-2%TiC and A16061-4%TiC are fabricated by using K2TiF6 (Potassium hexafluorotitanate) and graphite powder. A16061 was melted in crucible, when the A16061 was melted then premixed K2TiF6 and graphite powder of measured quantity were added to the molten aluminium and held for 30 minutes at a temperature of 900° c. The molten mix was stirred by means of the stirrer for the uniform distribution of the reinforcement. The reaction between the K2TiF6 and molten solution releases Ti, the released Ti reacts with graphite powder to produce TiC particles. After 30 minutes the slag developed in the molten mix is removed and the molten mix is poured into the cast iron mould. Fig.l shows fabricated A16061-4%TiC composite rod. Energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscope (SEM) were performed on F E I Quanta FEG 200 - High Resolution Scanning Electron Microscope. Vickers micro hardness test were performed for to know the hardness of the fabricated MMCs. The test specimen developed for SEM and EDX testing were circular in shape with the

dimensions of 8 mm in diameter and 8 mm in thickness. The test specimens were well polished by using belt grinder and disc polisher. The developed test specimens were subjected to SEM for to know the arrangement of the TiC particles and their distribution in the matrix. Fig.2 and Fig.3 shows scanning electron images of the fabricated A16061-2%TiC and A16061-4%TiC composite material. The SEM image discovers the presence of TiC particles in the aluminium matrix and the size of the TiC reinforcement are 1 ^m and less than l^m. Fig.4 shows EDX analysis for A16061-4%TiC composite. From the Fig.4 it was identified that A16061-4%TiC test specimen consist the elements Al, Ti, C, Fe and Si. Vicker's micro hardness tests were performed at a load of 300 grams with 15 seconds dwell time. Table.l displays the results of Vicker's micro hardness, from these results it was investigated that the micro hardness value was increasing with the increase in wt% of TiC reinforcement.

Fig. 1. Fabricated A16061-4%TiC MMC rod

Fig. 2. SEM image for A16061-2%TiC Fig. 3. SEM image for A16061-4%TiC

Table 1. Micro hardness

Material Trial 1(HV) Trial 2(HV) Trial 3(HV) Average Hardness(HV)

A16061 54.4 56.0 52.7 54.3

A16061-2%TiC 60.8 57.7 57.9 58.8

A16061-4%TiC 60.9 65.4 62.0 62.7

2.2. Turning experimentdetails

Turning experiments were performed on Kirloskar made Turnmaster-35 lathe. Tool insert and tool holder specifications were given in Table.2. The cutting force was measured by Kistler dynamometer (model no 9857B) and charge amplifier model was 5070A. Turning experiments were done for 1 minute for each experimental run. Surface roughness was measured by using surface roughness tester made by Mitutoyo (model no SJ-210). The setup

of lathe and lathe tool dynamometer was shown in Fig.5. All the turning experiments were performed in dry cutting condition.

Fig. 4. EDX analysis for A16061-4%TiC

Fig. 5. Lathe and lathe tool dynamometer setup Table 2. Turning experiment details

Condition

Specification

Tool insert

Tool holder Tool insert(UCTC) Tool insert(PCD) Cutting speed(m/min) Feed rate(mm/rev) Depth of cut(mm)

Uncoated tungsten carbide(UCTC) & PCD

PSBNR-2525M12

SNMG120408 MTTT5100

TCMW16T30F-L1

40, 60, 80, 100 and 120

0.04,0.06, 0.08, 0.1 and 0.12

0.5, 0.75, 1, 1.25 and 1.5 mm

3. Results and discussion

Turning experiments were performed at different cutting speed, feed rate and depth of cut as specified in Table.2. Fig.6. shows the effect of cutting speed on cutting force for PCD insert. The effect of cutting speed was studied by taking feed rate as 0.1 mm/rev and depth of cut as 1 mm for five different cutting speeds. From the Fig.6 it was identified that cutting force was less at higher TiC reinforcement, this is due to less build-up edge formation, from the Fig.6 it was also investigated that the cutting force was less at higher cutting speeds this is because the work past the tool at faster rate. Fig.7 shows the effect of feed rate on cutting force for PCD insert. During turning feed rate is varied and cutting speed and depth of cut are maintained constant and taken as 120 m/min and 1 mm, from the Fig.7 it was observed that cutting force was increasing with increase in feed rate and the cutting force was less in higher TiC reinforcement MMC. Fig.8 shows the effect of depth of cut on cutting force by using PCD insert at different levels of depth of cut by taking feed rate as 0.1 mm/rev and cutting speed as 120 m/min and maintained constant for all ranges of depth of cut. From Fig.8 it was observed that cutting force was high in A16061 with 0%TiC and the cutting force was high at higher depth of cut this is because increase in depth of cut increases the tool contact area and raises cutting force. Fig.9 shows effect of surface roughness for PCD insert by varying the cutting speed and keeping feed rate and depth of constant and taken as O.lmm/rev and 1 mm respectively. From the Fig.9 it is investigated that the surface roughness (Ra) is increasing with the increase in wt% of TiC, by the addition of TiC

0%T¡C-PCD 2%TiC-PCD 4%TiC-PCD

40 60 80 100

Cutting speed(m/min)

Fig.6. Effect of cutting speed on cutting force for PCD

140 120 100 80 60 40 20 0

0%T¡C-PCD 2%TiC-PCD 4%TiC-PCD

0.04 0.06 0.08 0.1 Feed rate(mm/rev)

Fig.7. Effect of feed rate on cutting force for PCD

180 160 140 120 100 80 60 40 20 0

0.5 0.75 1 1.25

Depth of cut(mm)

Fig.8. Effect of depth of cut on cutting force for PCD

0%TiC-PCD ■2% TiC-PCD 4%TiC-PCD

1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0

40 60 80 100

Cutting speed(m/min)

Fig.9. Effect of cutting speed on Ra for PCD

0%TiC-PCD 2%TiC-PCD 4%TiC-PCD

1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0

0.04 0.06 0.08 0.1 Feed rate (mm/rev)

0%TiC-PCD 2%TiC-PCD 4%TiC-PCD

Fig.10. Effect of feed rate on Ra for PCD

3 0.8 ro

K 0.6 0.4 0.2 0

Depth of cut(mm)

Fig. 11. Effect of depth of cut on Ra for PCD

« 150

.<= 100

40 60 80 100

Cutting speed(m/min)

0%TiC-PCD 2%TiC-PCD 4%TiC-PCD

0%TiC-PCD 4%TiC-PCD 0%TiC-UCTC 4%TiC-UCTC

Fig.12. Effect of cutting speed on cutting force for PCD and UCTC

160 140 — 120 ä 100 •i2 80 •B 60

40 20 0

0.04 0.06 0.08 0.1 Feed rate(mm/rev)

0%TiC-PCD 4%TiC-PCD 0%TiC-UCTC 4%TiC-UCTC

Fig.13. Effect of feed rate on cutting force for PCD and UCTC

3 2.5 2

3 1.5 ro 0£

-1-1-1-1-1

40 60 80 100 120

Cutting speed(m/min)

Fig.15. Effect of cutting speed on Ra for PCD and UCTC

0.04 0.06 0.08 0.1 Feed rate(mm/rev)

0%TiC-PCD 4%TiC-PCD 0%TiC-UCTC 4%TiC-UCTC

0.5 0.75 1 1.25 1.5

Depth of cut(mm)

Fig.14. Effect of depth of cut on cutting force for PCD and UCTC

0%TiC-PCD 4%TiC-PCD 0%TiC-UCTC 4%TiC-UCTC

0%TiC-PCD 4%TiC-PCD 0%TiC-UCTC 4%TiC-UCTC

Fig.16. Effect offeed rate on Ra for PCD and UCTC

E 15 i re

0.5 0.75 1 1.25 1.5

Depth of cut(mm)

Fig.17. Effect of depth of cut on Ra for PCD and UCTC

reinforcement the hardness of the MMC is increased and machining of higher wt% TiC increases the formation of build-up edge and this effects the surface roughness. From the Fig.9 it was also identified that surface roughness was less at higher cutting speed, the increase in cutting speed results lower build-up edge and this gives lower surface roughness values. The Fig.10 shows the effect of Ra at different levels of feed rate by taking cutting speed and depth of cut as 120 m/min and 1 mm respectively, from the Fig.10 it was identified that Ra was increasing with increase in feed rate and the surface roughness was high for 4%TiC reinforcement. Fig.l 1 shows the effect of surface roughness by varying the depth of cut and maintaining cutting speed and feed rate as constant with the range of 120 m/min and 0.1 mm/rev respectively. From the Fig. 11 it was investigated that the surface roughness was high at higher depth of cut. Fig. 12 shows the effect of cutting force for PCD and UCTC (uncoated tungsten carbide) at different levels of cutting speed. The effect of cutting speed was studied by taking feed rate as 0.1 mm/rev and depth of cut as 1 mm. From the Fig.l2 it was identified that cutting force was less at higher TiC reinforcement and the cutting force was less at higher cutting speeds. From the Fig.l2 it was also investigated that the developed cutting forces are high by using uncoated tungsten carbide than that of PCD, the PCD insert is much harder than uncoated tungsten carbide insert so the PCD insert produces less cutting force. Fig.l3 shows the effect of cutting force for PCD and UCTC by varying the feed rate and maintaining constant cutting speed and depth of cut with 120 m/min and 1 mm, the cutting forces are increasing with the increase in feed rate and the developed cutting forces are less for PCD insert. Fig. 14 shows the effect of cutting force for PCD and UCTC by varying the depth of cut and maintaining constant cutting speed and feed rate with 120 m/min and 0.1 mm/rev, the cutting forces are increasing with the increase in depth of cut and the developed cutting forces are less for 4%TiC- PCD insert. Fig. 15 shows the effect of surface roughness for PCD and UCTC at different levels of cutting speed with constant feed rate and depth of cut of 0.1 mm/rev and 1 mm respectively, from the Fig.15 it was investigated that the surface roughness was decreasing with the increase in cutting speed and the surface roughness was increasing with the increase in wt% of TiC, during the turning of A16061-TiC with the uncoated tungsten carbide produces higher build-up edge so the surface roughness values are higher than that of PCD. Fig. 16 shows the effect of surface roughness for PCD and UCTC at different levels of feed rate with constant cutting speed and depth of cut of 120 m/min and 1 mm respectively, from the Fig.16 it was identified that the surface roughness was increasing with the increase in feed rate and the surface roughness produced by the PCD insert is found to be low. Fig.17 shows the effect of surface roughness for PCD and UCTC at different levels of depth of cut with constant cutting speed and feed rate of 120 m/min and 0.1 mm/rev respectively, from the Fig.17 it was investigated that the surface roughness was increasing with the increase in depth of cut, the increase in depth of cut increased the contact area of the tool and this produces higher build-up edge and generates higher surface roughness. From the Fig.17 it was also observed that the surface roughness generated by uncoated tungsten carbide was much higher than PCD insert due to higher build-up edge formation. Based on the results it was identified that the developed cutting forces are little higher by using uncoated

0%TiC-PCD 4%TiC-PCD 0%TiC-UCTC 4%TiC-UCTC

tungsten carbide insert and better surface roughness was obtained by using PCD insert. 4. Conclusion

In the present study A16061-2%TiC and A16061-4%TiC metal matrix composites were produced by in-situ technique. SEM and EDX tests were performed for to know the arrangement and presence of TiC particles. Vicker's micro hardness tests were performed and find out that the hardness of the A16061 was increased by the addition of TiC reinforcement. Turning experiments were performed on A16061-0%TiC, A16061-2%TiC and A16061-4%TiC MMC by using PCD insert and investigated that the cutting force and surface roughness are decreasing with the increase in cutting speed. The increase in feed rate and depth of cut generates higher cutting force and surface roughness. The cutting force and surface roughness produced during turning of A16061-0%TiC and A16061-4%TiC MMC were studied by using PCD and uncoated tungsten carbide insert, the cutting force and surface roughness developed by means of PCD are lower than uncoated tungsten carbide insert.

Acknowledgements

The authors are thankful to Dr. K. Leo Dev Wins, Head, CRDM, Karunya University, Coimbatore, India for accepting our request for to carry out this research in their research centre. The authors are also thankful to J. Jones Robin, K.Sivasankar and C.John Kennedy from Department of Mechanical Engineering, Karunya University for helping in fabrication and experimental work. The thanks also extend to the Nano technology research center, SRM University and Microlab, Chennai for providing the lab facility.

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