International Journal of Engineering and Manufacturing Science.

ISSN 2249-3115 Volume 7, Number 2 (2017), pp. 225-235

© Research India Publications

http://www.ripublication.com

Behavioral Study of Mechanical Properties and

Machining of Composite Material Fabricated by

Powder Metallurgy

Mohit Raj1 and Dr. Neeraj Kumar2

1M.Tech (MIE) Student 2Professor (ME), Department of Mechanical Engineering

Suresh Gyan Vihar university, Rajasthan, jaipur, 302017, India.

Abstract

This research fabricates three different type of composite material with

methodology of powder metallurgy. In which base material is copper

electrolyte powder and reinforcement materials are tungsten carbide, silicon

carbide and graphite. With the help of SEM, EDS and hardness test

Microstructure and properties were investigated to know effect of sintering

temperature and time (1 hour at 750 °C) on fabricated composite materials.

The result showed that Cu-SiC composite is having more uniform structure

visualized after the sintering, everywhere reinforcement material located in

base material. Machining of fabricated composite Cu-SiC is more easy

compare than other because it is having more material removal rate (MRR).

Keywords: Powder metallurgy, Composite Material, SEM, EDS, Hardness &

Milling Machining

1. INTRODUCTION.

Initially metal powder is taken in the form of their usual size to mix with other metal

powder in the assigned proportion of use. copper metals and its property regarding

performance like thermal conductivity, electrical conductivity and sometime

mechanical properties are use to be tested for many applications, The unusual

property of a copper metal is its specific strength, corrosion behavior, wear resistance

226 Mohit Raj and Dr. Neeraj Kumar

and its specific stiffness. Mechanical and electrical properties are also investigated at

coated and uncoated powder to enhance the property; thermal diffusivity and thermal

conductivity are lower for coated powder The use of copper graphite composite

mainly in electrical brushes, electrical contacts and bearings materials and many

application due to its good thermal and electrical property and its lubricating behavior

[1-3]. Addition of solid lubricant in the material improves its mechanical strength like

wear resistance and also provides smoothness in the composite. Hardness and

toughness increases of the copper based composites after the sintering at elevated

temperature. Tungsten carbide, which has high hardness and stability at high

temperature, can be used as a raw material for hard alloys in the case of carbide

particle reinforcement. Information regarding the Cu-WC is not more specified in the

many article or research due to its unusual behaviour. SiC could be used as

reinforcement to enhance the strength of copper matrix. Copper-SiC composites

combine both the superior ductility and toughness of copper and high strength and

high modulus of SiC reinforcements [4-6]. The composition of copper and these

reinforcement materials are based on soft and hard property of material. Copper and

graphite are soft, ductile and malleable material whereas silicon carbide, tungsten

carbide are hard in nature . Importance of these composites is about the low wear

resistance, more hardness, and high thermal stability and has uniform microstructure.

Reinforcement material are present in the composites are also investigated by three

method (quadrant count method, polygonal method, and by interparticle distances). A

metal matrix composite fabricated through in situ processing has finer powder

particles and exhibits outstanding mechanical properties [7-9]. This research

fabricates the different type composites with the help of uniform microstructure,

hardness, powder composition of uniform distribution over and inside the composite

and machining of composites.

2. EXPERIMENTAL

The size of the metal powder particles before milling was 120µm for copper powder,

but for reinforcement material graphite, tungsten carbide and silicon carbide had

150µm and all powders have 99.99pure.There are three process involved for making

sample from powder metallurgy in which milling, compaction and sintering.

2.1 Planetary ball mill

These metal powders are milled in the tungsten based milling jar having capacity of

100ml. The variable used in the milling as speed 400rpm, Ball: ration 3:1 and total

milling time was 10 hours for one sample. Each sample milled in the 25gm quantity

according to their respective composition 4%, 4% and 8% for the Cu-c, Cu-SiC and

Cu-WC.

Behavioral Study of Mechanical Properties and Machining of Composite… 227

Table 1: milled powder parameter

Milled used Planetary ball mill

Jar capacity 100ml

Jar material Tungsten based material

Ball: powder 3:1 (by weight)

Ball diameter 3mm

Milling speed 400rpm

Milling time 10hours

Processing control agent Toluene

Total milling time 7hours

Cleaning organic agent Acetone

Fig 1. Milled powder after the milling

[Source: MNIT Jaipur]

2.2 Compaction

For compaction each sample takes two minute for cold compact in high speed steel

Die which is in cylindrical shape. The pressure required for the compaction 54MPa,

and 40MPa, 40MPa for copper-graphite, copper-tungsten carbide and copper-silicon

carbide.

228 Mohit Raj and Dr. Neeraj Kumar

(a)

(b)

Fig 2. (a) Die (High speed steel) used for compaction

(b) UTM machine used as compaction process

[Source: SGVU, Jaipur]

The force was applied for this compaction was 6KN, 4.5KN, 4.5KN as in order like

above. This is the used value only for 12mm diameter compact made by the 13mm of

diameter Die with 1mm clearance at punch.

2.3 Sintering

Sintering was proceed in Air controlled (argon environment) and temperature

controlled environment for 1 hour at 750 °C. Total sintering time was 2hour in which

first 1 hour are being used to increase the temperature up to 750°C and second 1hour

are used for proper sintering in control atmosphere. After the 24hours the samples are

taken out from the furnace with enhanced property and strength.

Behavioral Study of Mechanical Properties and Machining of Composite… 229

(a)

(b)

Fig 3. (a) CVD thermal machine for sintering

(b) composites sample after the sintering 1) Cu-C 2) Cu - WC 3) Cu-SiC

[Source: MNIT, Jaipur]

2.4 SEM test

These are 2kx micrographs of the three composites as show in the figure. In the figure

a, it is clear visualized the mixing of reinforcement material in the copper is not

uniform at the right face of composite but in fig b, this is uniform structure and

uniform mixing of composite powder clearly visualized after the sintering,

everywhere material located with the reinforcement material. From fig c, smoothness

is visualized at the face but not uniform like in fig b. at the top face of this material

have voids and only bottom part of the composite are uniform.

230 Mohit Raj and Dr. Neeraj Kumar

Fig.4. SEM micrographs of (a) copper-graphite (b) copper-silicon carbide

(c) copper-tungsten carbide

[Source: AIRF, JNU, Delhi]

These micrographs taken under the view of some specified parts of the composites in

micro size. low magnification applied on these composites for their usual size. White

particles appear in sample are voids whereas black and light black colour are

reinforcement and base material.

2.5 EDS test.

In figure a, the variation copper and silicon carbide increasing when the object is

tested on the particular part. Red line denotes the copper variation uniformly in the

composite from deceasing to increasing order. In figure b, the variation changes of

tungsten carbide from left to right. Initially copper and tungsten carbide located at

equal level in the composite but after increasing left to right the variation change that

means the existence of copper only presence in the sample and again tungsten carbide

located at middle and then only tungsten carbide located in the rest of part.

Behavioral Study of Mechanical Properties and Machining of Composite… 231

10 20 30 40 50 60 70 80keV

0

5

10

15

20

25

30

35

40

cps/eV

Cu Cu C

Si

10 20 30 40 50 60 70 80

keV

0

5

10

15

20

25

30

35

40

cps/eV

Cu Cu W W W

C

(a) (b)

10 20 30 40 50 60 70 80keV

0

10

20

30

40

50

cps/eV

Cu Cu C

(c)

Fig 5. EDS test composition variation graphs(a) copper-silicon carbide

(b) copper-tungsten carbide (c) copper-graphite

[Source: AIRF, JNU, Delhi]

Now in figure c, the distribution of copper with graphite not more uniformly

distributed because take a look from left to right the presence of copper- graphite only

exists in starting but after increasing in right graphite only present at some part

232 Mohit Raj and Dr. Neeraj Kumar

2.6 Hardness test

For the hardness test Rockwell hardness tester is used for the measurement of

hardness in the scale of B0 to B90. Staring from copper-graphite hardness test the

Brinell scale was found B74 scale after the hardness test. Hardness of copper-tungsten

carbide the Brinell no hardness B75 and the last one is copper-silicon carbide the

Brinell no B78 is measured.

Fig 6. Rockwell hardness test.

[Source: SGVU, Jaipur]

2.4 Milling Machining

For machining of composite VMC machine is used for slot cutting on the sintered

sample. Weight of the samples are 3.08, 3, 3.18gm for Cu-C, Cu-SiC, Cu-WC. The

parameter used for the machining of composite as speed-2000rpm,depeth of each

sample 3mm,feed rate 100mm/min, diameter of cutting tool is 3mm, and tool type is

hand mill. Specific part of this sample is time of cutting 3.4 sec for copper-silicon

carbide and 3.2, 3.1 sec for rest of two samples equally.

Table 2: Machining parameter used for slot cutting

Name of

composites

Input parameter Output parameter

Speed in

rpm

Depth of cut

in mm

Feed rate in

mm/min

Cutting time

in sec

MRR in

gm/sec

1)Cu-C 2000 3 100 3.1 .051

2) Cu-WC 2000 3 100 3.2 .068

3) Cu-SiC 2000 3 100 3.4 .058

Behavioral Study of Mechanical Properties and Machining of Composite… 233

Fig 7. (a) Hand mill tool used for slot cutting

[Source: MSME, Jaipur]

After the cutting of material the weight are reduce to 2.92, 2.8, 2.96gm. From this

value it is easy to find the MRR (material removal rate) which is .051gm/sec,

.058gm/sec,0.068gm/sec for Cu-C, Cu-SiC Cu-WC.

4. RESULTS AND DISCUSSION

From the above experimental study SEM test, EDS test, Hardness test and the last

machining process on composite, compared in these three composite samples the

copper-silicon carbide is the best because this sample have good enough property

rather than other two samples of copper-tungsten carbide and copper-graphite. The

view of microstructure copper and reinforcement material is uniform in Cu-SiC

composite. But in the copper-tungsten carbide and copper-graphite the uniform

structure are not found as in Cu-SiC composite. EDS testing graphs of Cu-SiC defines

the composition is homogeneous as the mixing of reinforcement material up to 4%.

But in the next two composite, the mixture was not uniform as in figure a in the EDS

testing. In the figure b, the distribution of tungsten carbide is not uniform after the

copper in the right side in lower part. Like as in figure c ,copper-graphite composition

are also not in homogenous way because in figure c it has been cleared visualized that

the limit of copper over exists after the uniform composition with red lines. Hardness

test reveals from the above study, it is observed that copper- silicon carbide has more

Brinell hardness no than rest of two composite. From the experimental result the

copper-SiC composite have B78 Brinell hardness nowhere as copper-graphite and

copper-tungsten carbide has B75 and B73 Brinell hardness no. composites are

machined by using VMC (Vertical milling machine) machine for slot cutting at the

234 Mohit Raj and Dr. Neeraj Kumar

top part of the composite. In the composite the time taken for the slot cutting for

copper-silicon carbide was 3.4 sec while for other two samples the time was 3.2, 3.1

for copper-tungsten carbide and copper-graphite composite.

5. CONCLUSION

The following conclusions can be drawn from the present investigation:

1. Microstructure of the copper-silicon carbide is most uniform among these

composites. Distribution of reinforcement material in the copper uniformly

found, bonding strength comparatively high in Cu-SiC

2. According to EDS test the composition are also uniform throughout the

composite as located above in the figure Cu-SiC composite.

3. Rockwell hardness test is also higher in Cu-SiC than other two composite as

mention above.

4. Machining behavior of Cu-Sic is also considerable because MRR (material

removal rate) of Cu-SiC is higher than Cu-C but lower than Cu-WC.

5. Hence considering overall result, the Copper-SiC composite have good

property rather than other two composites.

REFERENCES

[1] JAROSLAV KOVACIK, STEFAN EMMER2, JOZEF BIELEK3,

THERMAL PROPERTIES OF Cu-GRAPHITE COMPOSITES, Department

of Physics, Faculty of Electrical Engineering and Information Technology,

Slovak of Technology, Ilkovi cova 3, 812 19 Bratislava, Slovak Republic.

[2] Mariana Matos, José M. Castanho, Maria T. Vieira, Composite

copper/stainless steel coated powders, ICEMS-Materials and Surface

Engineering Group, Mechanical Engineering Department, Polo II, University

of Coimbra, Coimbra, Portugal (2007).

[3] C.P. Samal, J.S. Parihar, D. Chaira, The effect of milling and sintering

techniques on mechanical properties of Cu–graphite metal matrix composite

prepared by powder metallurgy route, Department of Metallurgical and

Materials Engineering, National Institution of Technology Rourkela, Rourkela

769 008, Orissa, India (2013).

[4] Farid Akhtar, Syed Javid Askari, Khadijah Ali Shah, Xueli Du, Shiju Guo,

Microstructure, mechanical properties, electrical conductivity and wear

behaviour of high volume TiC reinforced Cu-matrix composites, Institute of

Powder Metallurgy, Materials Science Department, University of Science and

Behavioral Study of Mechanical Properties and Machining of Composite… 235

Technology Beijing, 100083, China(2007)

[5] NAIQIN ZHAO, JIAJUN LI, XIANJIN YANG, Influence of the P/M process

on the microstructure and properties of WC reinforced copper matrix

composite, School of Materials Science and Engineering, Tianjin University,

Tianjin 300072 (2004).

[6] G. F. Celebi Efe, I. Altinsoy, M. Ipek, S. Zeytin, C. Binda, Some properties of

Cu-SiC composites produced by powder metallurgy method, Sakarya

University, Engineering Faculty, Department of Metallurgy and Materials

Engineering, Esentepe Campus, 54187 Sakarya, Turkey (2009).

[7] S.F. Moustafa a, Z. Abdel-Hamid a, A.M. Abd-Elhay, Copper matrix SiC and

Al2O3 particulate composites by powder metallurgy technique, Central

Metallurgical Research and Development Institute, P.O. Box 87, Helwan,

Cairo, Egypt Faculty of Engineering, Helwan University, Cairo, Egypt(2000).

[8] Michal Besterci, Ivan Kohu´tek , Oksana Velgosova, Microstructural

parameters of dispersion strengthened Cu–Al2O3 materials, Institute of

Materials Research, SAS, Watsonova 47, 043 53,Kosice, Slovakia (2007).

[9] Mahani Yusoff, Radzali Othman, Zuhailawati Hussain, Mechanical alloying

and sintering of nanostructured tungsten carbide-reinforced copper composite

and its characterization, School of Materials and Mineral Resources

Engineering, Engineering Campus, University Sains Malaysia, 14300 Nibong

Tebal, Penang, Malaysia(2010).

[10] Jin-Chun Kiml , Ho-Jin Ryul, Ji-Soon Kim', Yong-Soon Kwon', Byoung-Kee

kim, School of Materials Science and Engineering, University of Ulsan San-29

Moogu-2 Dong, Nam-Gu, Ulsan, 680-749, Korea(2006).

236 Mohit Raj and Dr. Neeraj Kumar