1. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN IN –
INTERNATIONAL JOURNAL OF ADVANCED RESEARCH 0976
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
ENGINEERING AND TECHNOLOGY (IJARET)
ISSN 0976 - 6480 (Print) IJARET
ISSN 0976 - 6499 (Online)
Volume 3, Issue 2, July-December (2012), pp. 226-234
© IAEME: www.iaeme.com/ijaret.asp
©IAEME
Journal Impact Factor (2012): 2.7078 (Calculated by GISI)
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CHARACTERIZATION OF AlSiC METAL-MATRIX BY STIR-
CASTING
Mr. Amol D. Sable1, Dr. S. D. Deshmukh2
1
Student of M.E. (Manufacturing Engg), Jawaharlal Nehru Engineering College (JNEC),
Aurangabad, Dr. Babasaheb Ambedkar Marathwada University, Maharashtra, India, E-mail:
amol672006@gmail.com
2
Principal, Jawaharlal Nehru Engineering College (JNEC), Aurangabad, Dr. Babasaheb
Ambedkar Marathwada University, Aurangabad, Maharashtra,
India, E-mail: sdeshmukh47@rediffmail.com
ABSTRACT
A tremendous development of the present engineering sectors, Metal-matrix composites
plays a vital role in industrial metallurgical processes. The metal-matrix composite has a
great advantageous properties and reasonable costing increases the performance of the
machineries and it also much more profitable technology than powder metallurgical
processes. Metal-matrix composites can mainly prepared by metallic materials, ceramic
materials and non-metallic materials. In this paper, we adopted the metallic material like
aluminium with silicon carbide (AlSiC) metal-matrix composites by stir-casting method. On
the explore and augmentation of the engineering industrial sectors, this paper emphasizes the
production of metal-matrix AlSiC composites by the continuous stir-casting method and
prepared six rounded bars and six square bars samples of changeable percentile compositions
of SiC – 5%, 10%, 15%, 20%, 25% and 30% with aluminium. Final samples were tested by
hardness using Brinell hardness machine, impact strength test using Charpy-V-Notched
machine and Microstructure examination conducted on Trinocular type Metallurgical
Microscope.
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2. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
Keywords: Metal-Matrix Composite, AlSiC Stir-Casting, Hardness Test, Impact Strength
Test, Microstructure Examination
I. INTRODUCTION
Metal-matrix composites has great role in the modern engineering fields. These are used for
the manufacturing the strong, hard and light-weighted engineering materials which sere used
in latest machineries, parts of the speedy motors and vehicles and other engineering works.
Silicon carbide is very important constituents of the metal-matrix composites because of its
excellent homogeneous uniting properties. It also the back bone of every structure metal-
matrix composites. Metals like aluminium, magnesium, zinc, manganese, ferrous etc are used
for fabricating the metal-matrix composites; here we prepared AlSiC metal-matrix. The raw
materials like Al (98.41%) metal scraps homogeneously united with SiC (320 grit) by
continuous stir-casting method. Stir-casting is the type of vortex heating with stirring method
in which the raw materials gets homogeneously mixed with each other at controlled
temperature rate. The slurry was poured into the desired shaped moulds i.e. rounded bars and
rectangle bars. By this method, we prepared the samples of different composition of AlSiC
metal-matrix and then the testing treatments like hardness impact strength and micrograph
structure analysis would be done which is discussed in this paper.
II. METAL-MATRIX COMPOSITES
Metal-matrix composite structure is generally designated purely by the term metal alloy of
the matrix and the material in the form of the strengthening. The matrix is permeating soft
part generally having excellent tensile strength, hardness, ductility and thermal conductivity
which are set in the hard reinforcements having high tautness and low thermal expansion. For
the development of metal-matrix, light metal composite materials mixed with light metal
alloys are applied as matrix materials. During the metal-matrix production, the main
contribution of special alloys is used in powder metallurgy which is used for the
solidification.
III. STIR-CASTING EXPERIMENTATION
Stir Casting is a liquid state method of composite materials fabrication, in which dispersed
phase is mixed with a molten metal-matrix by means of mechanical stirring. The liquid
composite material is then cast by conventional casting methods. The term stir-casting is the
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3. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
process of stirring molten metal’s are used for continuous stirring particles into metal alloy to
melt and immediately pour into the sand mould then cooled and allow to solidify.
The experimental arrangement has been assembled by the coupling motor and mild steel four
blade stirrer on the MS square pipes frame. The melting of the alluminium (98.41%) scraps
and silicon carbide powder (SiCp – 320 grit size) is carried out in the graphite crucible in to
the coal-fired furnace. First the scraps of aluminium (98.41%) were preheated for 3 to 4 hours
at 450°C and silicon carbide powder (SiCp – 320 grit size) also heated with 900°C and both
the preheated mixtures is then mechanically mixed with each other below their melting
points. This metal-matrix AlSiC is then poured into the graphite crucible and put in to the
coal-fired furnace at 760°C temperature. After completing the experiment the slurry has been
taken into the sand mould within thirty seconds allow it to solidify. Finally we prepared the
six types varying samples like rounded bars and square bars as per specified by the objectives
this paper. This experiment should repeatedly conducted by varying the compositions of the
composite powder of SiC (5%, 10%, 15%, 20%, 25% and 30%) as shown in the fig.1 given
below;
After getting the final samples i.e. rounded bars and square bars, it is then ready for the
testing of hardness test, impact strength test and micrograph examination.
IV. CONDUCTED TESTS
The main purpose this paper is to develop the strong light weighted metal-matrix AlSiC
composite material which is useful in the industrial sectors as well as advanced machineries.
After fabrication following test were conducted by this paper;
4.1 Hardness Test (Brinell Hardness Test)
Hardness test has been conducted on each specimen using a load of 500 Kg and a steel ball of
diameter 10 mm as indenter. Hardness tester is employed to evaluate the interfacial bonding
between the particles and the matrix by indenting the hardness with the constant load and
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4. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
July December
constant time. Test samples were sectioned from the cylindrical cast bars of size 30 mm
diameter and 30 mm height. Test specimens before test and after test are shown in given fig.
est
2; the mean result of the specimens trials are shown in the chart No.1 and its graphical
representations are given in the graph No.1;
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5. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
4.2 Impact Strength test
Impact Strength test is done by Charpy V Notch pendulum impact testing machine. The
square bar test specimens is applied on a simply supported beam. A Specimen is adjusted by
square cross section 10 mm x 10mm x 55mmin length with 45 degree v notch at center.
Single blow of hammer is given at mid span of specimen. The blow should be sufficient to
bend or break the specimen at center. The striking energy should be 310 ±10 joules. The
energy spent in bending or breaking the specimen is taken as Charpy impact value shown in
the fig. 3, the mean result of the specimens trials are shown in the chart No.2 and its graphical
representations are given in the graph No.2;
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6. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
4.3 Microstructure Examination
Metallographic samples were sectioned from the cylindrical cast bars. A 0.5 % HF solution
was used to etch the samples wherever required. To see the difference in distribution of SiC
particles in the aluminum matrix, microstructure of samples were developed on
Trinocular type Metallurgical Microscope (Made: JVC, Range-X10 to X1000) shown in the
fig.4;
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7. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
July December
First sample was prepared without applying any stirring process as shown in fig. 5. When the
5
composite has been developed without applying stirring process, particle clustering occurred
in some places, and some places were identified without SiC inclusion. This was due to the
fact that when the SiC particles were added into the molten alloys, they were observed to be
alloys,
floating on the surface, though they have a large specific density than the molten metal. This
was due to high surface tension and poor wetting between the particles and the melt.
A group of figures depicts micrographs of samples containing 5%, 15%, 25% SiC by weight
f
respectively developed with the help of two step mixing method of stir casting. It clearly
two-step
shows the resulting homogeneous distribution of particles in the samples as shown in the fig.
6;
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8. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
Figure 7 shows micrograph of sample containing 30% SiC by weight. Density of SiC
particles decreases inspite of an increase in concentration. This may be attributed to the fact
that a this weight fraction, SiC particles greatly interact with each other leading to clustering
of particles and consequently settling down.
V. RESULT AND CONCLUSION
After getting the result of the composition AlSiC (5%, 10%, 15%, 20%, 25% and
30%) ready samples were tested and checked the hardness test, impact of strength test
and uniform distribution study of reinforcement in metal-matrix with micro-
spectrograph analysis as follows;
1) The results of study suggest that with increase in composition of SiC, an increase in
hardness and impact strengths have been observed.
2) The best results has been obtained at 25% weight fraction of 320 grit size SiC
particles. Maximum Hardness = 44.9 BHN and Maximum Impact Strength = 35.33 J.
3) Homogenous dispersion of SiC particles in the Al matrix shows an increasing trend in
the samples prepared by without applying stirring process with manual stirring and
with 2-Step method of stir casting technique respectively.
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9. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
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