Materials Today: Proceedings 20 (2020) 217–221

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Materials Today: Proceedings

journal homepage: www.elsevier.com/locate/matpr

Studies on Bottom ash strengthened LM13 composite

Maharaja Gowda B ⇑, Raghavendra Joshi, Rajashekhara Kuntanahal
Ballari Institute of Technology and Management, Ballari 583104, India

a r t i c l e i n f o a b s t r a c t

Article history: Recent times, the composite materials are extensively used due to their compliance to diverse circum-
Received 22 August 2019 stances and the virtual ease of amalgamation with supplementary materials to provide explicit functions
Received in revised form 8 November 2019 and reveal enviable properties. The application of the same is ornamental to an immense level in any of
Accepted 11 November 2019
the field including engineering field. Metal Matrix Composites in short MMCs with less expansive and
Available online 28 November 2019
low density increases the demand in various applications of industrial sector. The present work uses
the Bottom ash as reinforcement in MMCs which is a low density and inexpensive spin-off procured dur-
Keywords:
ing ignition of coal in thermal power plant. Bottom ash particles are prepared to a grain size of 74 nm to
LM13 alloy
Bottom ash
114 nm using ball milling. Basic matrix LM13 alloy is reinforced with Bottom ash particles to prepare
Stir casting MMCs using stir casting method. Reinforcement of Bottom ash is done in terms of weight percentages
SEM ranging from 0 to 8 in steps of 2. Composite specimens are prepared as per ASTM standard using cast
X-ray diffraction ingots. Micro-structural examination of composite specimens is carried out to know the dispersion of
Mechanical properties bottom ash particle in LM13 matrix using SEM and X-ray diffraction test. At the end, the mechanical
properties such as tensile, compression and hardness of specimens is evaluated by varying percentage
of Bottom ash and found significant improvement in the same.
Ó 2019 Elsevier Ltd. All rights reserved.
Selection and peer-review under responsibility of the scientific committee of the International
Conference on Recent Research Emerging Trends in Materials & Mechanical Engineering.

1. Introduction in aluminium metal matrix composite and evidenced that it can

enhance mechanical properties in turn widely used in light weight
Presently the metal matrix composites are a family of novel vehicles applications [6]. Bottom ash as a solid residue is one of the
ingredients practicing vigorous advancement in assorted fields. disposable product to despite the use of the bottom ash in con-
The potential of MMCs materials have gained significant an struction materials, it can also used as an reinforcement in the
improvement in performance over conventional alloys has been MMC’s which will be also an alternative for the traditional material
widely recognized. Another key factor is the cost in determining from thermal power plant [1]. The characteristics of A356 alloy
the applications apart from performance. The overall cost effective- reinforced with bottom ash by stir casting method little improve-
ness of the material rely on application in addition to material cost. ment over the strength to weight ratio, hardness, yield strength
Also it depends on the process through which the material and tensile strength but decreases in ductility [3]. Aluminium
advances. Properties of aluminium alloys such as low density, matrix composites toughened with weight percentage of 5% fly
detoriation and wear resistance, less thermal coefficient of expan- ash particle has been prepared using stir squeeze cast method.
sion rendered for various applications compared with conventional Abrasive wear test has been done to determine the wear resistance
metals and alloys. Al2024 reinforced with Al2O3 particles as rein- against different speed and loads. Results have shown an improve-
forcement up to 30% prepared by peak method and consequence ment in the abrasive wear resistance [4,5].
tested pressure and studied the effect of porosity and other prop-
erties [2,7]. Currently, the fly-ash particles are used as reinforce-
2. Material selection and preparation
ment due to low cost, low density and as well it is the waste by-
product from thermal power plant and industries. Further, used
2.1. Matrix materials

⇑ Corresponding author. LM13 alloy have the properties like high strength and hardness
E-mail address: maharajagowdab@gmail.com (M. Gowda B). at higher operating temperature. It is having better confrontation

https://doi.org/10.1016/j.matpr.2019.11.119
2214-7853/Ó 2019 Elsevier Ltd. All rights reserved.
Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Research Emerging Trends in Materials & Mechanical
Engineering.
218 M. Gowda B et al. / Materials Today: Proceedings 20 (2020) 217–221

Table 1
Chemical composition of LM13.

Cu Zn Mg Si Ni Fe Mn Pb Sn Ti Al
0.7% 0.5% 1.5% 12% 1.5% 1% 0.5% 0.1% 0.1% 0.2% Bal

Table 2
Chemical composition of Bottom ash.

SiO2 AlO3 FeO3 CaO MgO NaO2 K2O

53.6% 28.3% 5.8% 0.4% 4.2% 1.0% 0.3%

to bear, superior bearing chattels, and a little coefficient of thermal

expansion which will allows us to use in IC engine components like
piston and connecting rod. Also, it is having fluidity property which
is useful in casting intricate components with thin cross section
like connecting rod. The chemical composition of the same in
terms of weight percentage is tabulated in Table 1.

2.2. Reinforcement material

The Bottom ash is used as reinforcement particles that are col-

lected from Ballari thermal power station, Karnataka. The rein-
forcement particles with average dry density 1.4 g/cc are used.
The bottom ash is prepared to the average of 100 nm grain size
through ball milling process. The chemical symphony of the same
in terms of weight percentages is listed in Table 2.
The components are prepared through liquid metallurgical pro-
cess due to certain advantages pertaining to low operating cost and
moderately simplicity of producing intricate pieces. Though the
devices and processes are distinctively well-matched for
unstrengthened metals or alloys, all of them have various detri-
mental things which makes impracticable facsimile of proportions
to close tolerances. Further using them in the production of tough-
ened materials, the outcome is prominent due to short of clear-cut
control over route constraints [8]. Manual controlled electrical
Resistance furnace is used to melt aluminium alloy. LM13 alloy is
poured in crucible and in turn it is kept in furnace chamber and
closed using blanket for melting the same. The temperature of
350 °C is set for 1st cycle with duration of 30 min. Further it is con-
tinued the melting process raising the temperature up to 740 °C for
2nd, 3rd and 4th cycles with time duration of 30mins, 30 min and
60 min respectively. Fig. 1 shows the heating furnace along with
control unit. The quantity of reinforcement and matrix ratio in
terms of weight percentage is publicized in Table 3.
Certain measures such as even distribution of reinforcement
material and feasible vertex have been taken to prepare the test
samples. However, the vertex obtained may lead to trap the air
bubbles and as well stirring speed influences the uniform distribu-
Fig. 1. (a) Pouring of molten metal into the die; (b) Removing of cast composite
tion of bottom ash particles. Stirrer is made of high carbon steel. from die.
The speed of the stirrer is around 220 rpm with a time period of
10 min for all weight percentage of reinforcement in LM13. The
degassing tablet namely Hexachloroethane (C2Cl6) is used to Table 3
remove few dissolved gasses before pouring and then allowed for The amount of reinforcement and matrix in composite.

solidification as shown in Fig. 1(a). The outcome of the process is LM13 in grams 1500 1470 1440 1410 1380
shown in Fig. 1(b). Bottom ash in grams 0 30 60 90 120

2.3. Specimen preparation 3. Result & discussions

The samples were prepared for the various tests as per the 3.1. Scanning electron microscopy (SEM)
ASTM standard. The photographs of the specimens prepared are
shown in Fig. 2(a) for tensile test, 2 (b) for compression test and Fig. 3(a) and (b) shows the SEM images for the composite spec-
2 (c) for hardness respectively. imens reinforced with 2% and 6% of bottom ash. It has been
 M. Gowda B et al. / Materials Today: Proceedings 20 (2020) 217–221 219

composition of the prepared samples has been evaluated using EDS

process. The solid surface of specimen was prepared by using dif-
ferent grits of emery paper after the surface is etched with Gold/
Palladium liquid agent for the analysis of microstructure. The
result indicates lesser sputter rates as the Au/Pd alloy (60/40 and
80/20) is less competent to coat than with pure gold. Au/Pd is over
and over again suggested to get a smaller grain dimension. Au/Pd
does upshot in slighter grain size when evaporated in high vac-
uum, however used in SEM sputter coaters the disparity among
Au and Au/Pd is scarcely detectable. Pd alloy is less appropriate
for heat perceptive samples and as well for EDX analysis due to
extra set of peaks.

3.2. Energy Dispersive Spectroscopy (EDS) micrograph study on weight

of 6% prepared AMMC’s

Fig. 4 shows the EDS result that reveals the information about
quantity and type of chemical element present after the addition
of reinforcement. It also assists to assess multi-layer thickness of
metallic coatings and analysis of various alloys.

3.3. Tensile strength

Fig. 5 shows the effect of Bottom ash particle in wt % on ulti-

mate tensile strength. It has been observed that the addition of
Bottom ash particle improves the tensile strength of composites.
Bottom ash as a reinforcement material contains hard particles
along with soft ductile in nature of LM13 matrix improvises the
tensile strength. This will be endorsed to develop high lasting
stress all through solidification and due to miss-match of thermal
expansion between particle and soft Al matrix. The increase in
strength may also be outcome of compactness of reinforcement
with soft aluminium matrix. Wetability is one of the resisting cri-
teria for the occurrence of better bonding between reinforcement
and matrix. This indicates an improvement of the tensile strength
of the composite.

3.4. Compression strength results

The result of Bottom ash particle in wt % on yield compressive

strength obtained from uniaxial compression load can be shown
in Fig. 6. Addition of Bottom ash particle at 6 wt% causes an
improvement in compressive stress. Beyond 6 wt% of Bottom ash
particles, the compressive stress is decreased. The cavity is formed
at an interface of Bottom ash particle and matrix that experiences
tensile loading. This cavity formation lowers the composite proper-
ties because of the lowered in load transfer from matrix to fiber

3.5. Hardness results

Fig. 2. Specimen prepared as per ASTM for (a) Tensile test; (b) Compression; (c) Fig. 7 shows hardness value of LM13 and the composite con-
Hardness test. taining varying Wt% of Bottom ash particle. It shows that the addi-
tion of Bottom ash particle in LM13 matrix improve the hardness
value of composites up to 6 wt% and beyond 6 wt% of Bottom ash
particle with LM13 reduces. The dispersion of Bottom ash particle
observed that the dispersion of average size of the reinforced par- improves the hardness, as particle are hardness more than LM13,
ticles with different orientation at various points throughout the and provides their inherent characteristics of hardness value to soft
specimen. Also, it has exhibited crystalline structure. The chemical matrix.
220 M. Gowda B et al. / Materials Today: Proceedings 20 (2020) 217–221

Fig. 3. The microstructure of the different specimens containing LM13 reinforced with Bottom ash (a) 2% Weight of Bottom ash; (b) 6% Weight of Bottom ash.

Fig. 4. Assessment and evaluation based on Energy Dispersive Spectroscopy (EDS) micrograph study.
 M. Gowda B et al. / Materials Today: Proceedings 20 (2020) 217–221 221

properties from the analysis. The following conclusions are drawn

and as follows:

(i) From the microstructure studies such as SEM and EDS

micrographs it is revealed that the composite fabrication
has fairly even dispersion of bottom ash particle in the
LM13 matrix.
(ii) By adding Bottom ash particles in varying Wt% in LM13 signif-
icantly improved ultimate tensile strength of MMCs com-
pared to unreinforced matrix of LM13. The ultimate tensile
strength of Bottom ash/LM13 composite has been improved
by 60.20% at 6 wt% of Bottom ash reinforcement. However,
the ultimate tensile strength slowly decreased above 6 wt%
of Bottom ash. It has been found that the Brinell hardness num-
Fig. 5. Effect of Bottom ash wt % on tensile strength of composites.
ber of the specimen increases with increase in the wt% of
the reinforcement particles. It was noticed that the maximum
harness value is 109 BHN for 6 wt% of bottom ash particles.
(iii) Adding of Bottom ash in LM13 matrix clearly showed
improvement in compressive strength up to 6 wt%. It has
been noticed that the decrease in value of compressive
strength by adding above 6 wt% of Bottom ash.
Overall it has been concluded that there is an improvement in
the mechanical properties of the bottom ash reinforced LM13 com-
posite specimen.

Declaration of Competing Interest

The authors declare that they have no known competing finan-

cial interests or personal relationships that could have appeared
to influence the work reported in this paper.
Fig. 6. Effect of Bottom ash wt % on compressive strength of composites.
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