By P.vinod Final Year M.tech(nano Technology) Department Of Metallurgical Engineering Andhra University College Of Engineering (a) Visakhapatnam
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By P.VINOD Final Year M.Tech(Nano Technology) Department OF Metallurgical Engineering Andhra university college of engineering (A) Visakhapatnam
CONTENTS 1
INTRODUCTION
2
OBJECTIVES
3
EXPERIMENTAL DETAILS
4
RESULTS AND DISCUSSIONS
5
CONCLUSIONS
INTRODUCTION
1.
Nanotechnology literally means any technology performed on a nano scale that has applications in the real world.
2.
The Present Work Considered metal matrix composites reinforced with NANO sized discrete particles.
3.
The term “composite” broadly refers to a material system which is composed of a discrete constituent (the reinforcement) distributed in a continuous phase (the matrix).
4.
Conventional stir casting technology has been employed for producing particulate reinforced metal matrix composites.
The major problem in this technology is to obtain sufficient wetting of dispersion by the liquid metal and to get a homogeneous dispersion of the ceramic particles.
In AMCs one of the constituent is aluminum/aluminum alloy, which forms percolating network and is termed as matrix phase.
The other constituent is embedded in this aluminum/aluminum alloy matrix and serves as reinforcement,.
Advantages of AMCs over unreinforced materials Greater strength Improved stiffness Reduced density (weight) Improved high temperature properties Controlled thermal expansion coefficient Thermal/heat management Enhanced and tailored electrical performance Improved abrasion and wear resistance Control of mass (especially in reciprocating applications) Improved damping capabilities.
OBJECTIVE
The objective of this work is to produce a nanocomposite and observe the hardness values.
The effects of Sic particle content on the hardness of the composites were investigated.
Based on experiments, hardness was improved by incorporation of nano-Sic into matrix.
The improvement in values of hardness was observed in this experiment is due to small particle size and good distribution of the Sic particles.
EXPERIMENTAL WORK
Materials 1. 2.
1 kg Aluminum ignot(99% purity) 60 grams of silicon carbide(197nm)
Practical Equpiment 1. 2. 3. 4. 5.
High energy planetary ball milling X-ray diftractometer Clay-graphite crucible in a resistance furnace. Graphite stirrer Muffle furnace
High energy ball milling
The reduction in particle size of silicon carbide from micron level to the nano level was carried out using a high-energy planetary ball mill.
The ball mill was loaded with BPR (Ball to powder weight ratio) of 10:1.
The rotation speed of the planet carrier was 200 rev min-1.
First 60 grams of silicon carbide powder was taken and ball mill it for 15 hours with the 3 mm balls. Another 20 hours milled with 2mm balls.
The sample was taken out after every 5 hours of milling.
After the completion of each 5 hours checked it for crystallize size using XRD
High Energy Planetary Ball Mill (Model: Retsch, PM 100, Germany)
Vial- Balls- Lid-Gasket Set
X - RAY DIFFRACTION STUDIES In order to characterize the silicon carbide powder by using X-Ray
Diffract meter.
we have to take the silica glass plate and disperse the powder uniformly on the space providing on it.
Take 10mm divergence slit in order pass the X-rays through the sample.
The samples were scanned in the range from 15 to 90 degrees 2-θ and analyzed for crystallite size, peak height and crystallinity by using X-Ray Diffractometer
X-Ray Diffractometer (Model: 2036e201; Rigaku, Ultima Iv, Japan)
Closer View of the Set Up
STIR CASTING OF COMPOSITE
o
Thepure aluminum alloy was used as a matrix material.
o
Fly-ash powder was added as reinforcement particles.
o
All the melting was carried out in a clay-graphite crucible in a resistance furnace.
o
The furnace temperature was first raised above the liquidus to melt the aluminum alloy completely.
o
At this stage Fly-ash particles were added and mixed manually.
o
when the aluminum alloy was in a semi-solid state and then automatic mechanical mixing was carried out for 10 minutes by using an graphite stirrer an average stirring rate of 550-650 rpm.
o
In the final mixing processes, the furnace temperature was controlled to be within 730±10 °C.
o
Mechanical stirring could indeed mix the particles into the melt.
o
After the composite preparation the samples are homogenized at the temperature of 1800c for 30 hours in a muffle furnace.
o
For each two hours we have collected the samples and observe the Rockwell B scale (1/8 inch red indenter) hardness of each sample.
Schematic Representation of Dispersion Process
RESULTS AND DISCUSSIONS
HIGH ENERGY BALL MILLING
Milling chamber and balls were made of tungsten carbide and the balls were of 3mm, and 2mm diameter.
The total duration selected for milling was 35 hours.
First 60 grams of silicon carbide powder was taken and ball mill it for 20 hours with the 3 mm balls.
Another 15 hours with 2mm balls
The sample was taken out after every 5 hours of milling.
Crystallite size was checked using XRD
X - RAY DIFFRACTION STUDIES
The X-ray diffraction measurements for ball milled samples were carried out with the help of a Goniometer model 2036E201 using Cu Kα radiation (Kα= 1.54056 A0) at an accelerating voltage of 40 KV and a current of 20 mA.
The samples were scanned in the range from 15 to 75 degrees 2-θ and analyzed for crystallite size, peak height and crystallinity by using X-Ray Diffractometer
xrd results showing intensity versus 2 theta angle for different samples which are taken at regular intervals
esults showing intensity versus 2 theta angle for samples of initial and final sam
CRYSTALLITE SIZE DETERMENATION
The average crystallite size was determined from the full width at half maximum (FWHM) of the X – ray diffraction peak using Scherer’s equation.
Crystallite size = (kλ) / (FW(S)*cosθ)
wavelength λ=1.548 A0
FW(S) ^D=FWHM^D-FW (I) ^D
No of Hours
2theta
FWHM
Crystalite Size(nm)
0
26.617
0.120
197.93
5
26.617
0.128
151.29
10
26.618
0.133
133.29
15
26.617
0.136
124.23
20
26.618
0.138
119
25
26.617
0.151
94.95
30
26.617
0.163
80.61
35
26.602
0.189
61.53
variation in crystallite size with milling time.
HARDNESS TESTING
stir casting samples
Aluminum metal may be hardened by the uniform dispersion of the 2% volume of the in silicon carbide particles of very hard and inert materials.
Strengthening mechanism involves interaction between the particles and dislocations within the matrix, as with precipitation hardening.
After completion of the stir casting procedure the samples are homogenized.
The samples are collected at regular intervals and check hardness values using Rockwell B scale.
No Of Hours
Rockwell Hardness
2
22.5
4
38
6
55.5
8
68.5
10
72
12
74
14
76
16
79
18
82
20
84
22
86
24
86
26
86
28
86
Rockwell hardness reference to time.
values
with
Hardness vs. Time.
CONCLUSIONS
1.
The crystallite size of the silicon carbide powder was reduced from 197 nano meters to the 58 nano meters.
2. The Rockwell B scale hardness values are increasing with the homogenizing time. 3. The values of hardness are initially 22.5 and after homogenizing it for 28 hours in the muffle furnace.The final value is reached up to 86. 4. the hardness values improved .
THANK YOU
CONTENTS 1
INTRODUCTION
2
OBJECTIVES
3
EXPERIMENTAL DETAILS
4
RESULTS AND DISCUSSIONS
5
CONCLUSIONS
INTRODUCTION
1.
Nanotechnology literally means any technology performed on a nano scale that has applications in the real world.
2.
The Present Work Considered metal matrix composites reinforced with NANO sized discrete particles.
3.
The term “composite” broadly refers to a material system which is composed of a discrete constituent (the reinforcement) distributed in a continuous phase (the matrix).
4.
Conventional stir casting technology has been employed for producing particulate reinforced metal matrix composites.
The major problem in this technology is to obtain sufficient wetting of dispersion by the liquid metal and to get a homogeneous dispersion of the ceramic particles.
In AMCs one of the constituent is aluminum/aluminum alloy, which forms percolating network and is termed as matrix phase.
The other constituent is embedded in this aluminum/aluminum alloy matrix and serves as reinforcement,.
Advantages of AMCs over unreinforced materials Greater strength Improved stiffness Reduced density (weight) Improved high temperature properties Controlled thermal expansion coefficient Thermal/heat management Enhanced and tailored electrical performance Improved abrasion and wear resistance Control of mass (especially in reciprocating applications) Improved damping capabilities.
OBJECTIVE
The objective of this work is to produce a nanocomposite and observe the hardness values.
The effects of Sic particle content on the hardness of the composites were investigated.
Based on experiments, hardness was improved by incorporation of nano-Sic into matrix.
The improvement in values of hardness was observed in this experiment is due to small particle size and good distribution of the Sic particles.
EXPERIMENTAL WORK
Materials 1. 2.
1 kg Aluminum ignot(99% purity) 60 grams of silicon carbide(197nm)
Practical Equpiment 1. 2. 3. 4. 5.
High energy planetary ball milling X-ray diftractometer Clay-graphite crucible in a resistance furnace. Graphite stirrer Muffle furnace
High energy ball milling
The reduction in particle size of silicon carbide from micron level to the nano level was carried out using a high-energy planetary ball mill.
The ball mill was loaded with BPR (Ball to powder weight ratio) of 10:1.
The rotation speed of the planet carrier was 200 rev min-1.
First 60 grams of silicon carbide powder was taken and ball mill it for 15 hours with the 3 mm balls. Another 20 hours milled with 2mm balls.
The sample was taken out after every 5 hours of milling.
After the completion of each 5 hours checked it for crystallize size using XRD
High Energy Planetary Ball Mill (Model: Retsch, PM 100, Germany)
Vial- Balls- Lid-Gasket Set
X - RAY DIFFRACTION STUDIES In order to characterize the silicon carbide powder by using X-Ray
Diffract meter.
we have to take the silica glass plate and disperse the powder uniformly on the space providing on it.
Take 10mm divergence slit in order pass the X-rays through the sample.
The samples were scanned in the range from 15 to 90 degrees 2-θ and analyzed for crystallite size, peak height and crystallinity by using X-Ray Diffractometer
X-Ray Diffractometer (Model: 2036e201; Rigaku, Ultima Iv, Japan)
Closer View of the Set Up
STIR CASTING OF COMPOSITE
o
Thepure aluminum alloy was used as a matrix material.
o
Fly-ash powder was added as reinforcement particles.
o
All the melting was carried out in a clay-graphite crucible in a resistance furnace.
o
The furnace temperature was first raised above the liquidus to melt the aluminum alloy completely.
o
At this stage Fly-ash particles were added and mixed manually.
o
when the aluminum alloy was in a semi-solid state and then automatic mechanical mixing was carried out for 10 minutes by using an graphite stirrer an average stirring rate of 550-650 rpm.
o
In the final mixing processes, the furnace temperature was controlled to be within 730±10 °C.
o
Mechanical stirring could indeed mix the particles into the melt.
o
After the composite preparation the samples are homogenized at the temperature of 1800c for 30 hours in a muffle furnace.
o
For each two hours we have collected the samples and observe the Rockwell B scale (1/8 inch red indenter) hardness of each sample.
Schematic Representation of Dispersion Process
RESULTS AND DISCUSSIONS
HIGH ENERGY BALL MILLING
Milling chamber and balls were made of tungsten carbide and the balls were of 3mm, and 2mm diameter.
The total duration selected for milling was 35 hours.
First 60 grams of silicon carbide powder was taken and ball mill it for 20 hours with the 3 mm balls.
Another 15 hours with 2mm balls
The sample was taken out after every 5 hours of milling.
Crystallite size was checked using XRD
X - RAY DIFFRACTION STUDIES
The X-ray diffraction measurements for ball milled samples were carried out with the help of a Goniometer model 2036E201 using Cu Kα radiation (Kα= 1.54056 A0) at an accelerating voltage of 40 KV and a current of 20 mA.
The samples were scanned in the range from 15 to 75 degrees 2-θ and analyzed for crystallite size, peak height and crystallinity by using X-Ray Diffractometer
xrd results showing intensity versus 2 theta angle for different samples which are taken at regular intervals
esults showing intensity versus 2 theta angle for samples of initial and final sam
CRYSTALLITE SIZE DETERMENATION
The average crystallite size was determined from the full width at half maximum (FWHM) of the X – ray diffraction peak using Scherer’s equation.
Crystallite size = (kλ) / (FW(S)*cosθ)
wavelength λ=1.548 A0
FW(S) ^D=FWHM^D-FW (I) ^D
No of Hours
2theta
FWHM
Crystalite Size(nm)
0
26.617
0.120
197.93
5
26.617
0.128
151.29
10
26.618
0.133
133.29
15
26.617
0.136
124.23
20
26.618
0.138
119
25
26.617
0.151
94.95
30
26.617
0.163
80.61
35
26.602
0.189
61.53
variation in crystallite size with milling time.
HARDNESS TESTING
stir casting samples
Aluminum metal may be hardened by the uniform dispersion of the 2% volume of the in silicon carbide particles of very hard and inert materials.
Strengthening mechanism involves interaction between the particles and dislocations within the matrix, as with precipitation hardening.
After completion of the stir casting procedure the samples are homogenized.
The samples are collected at regular intervals and check hardness values using Rockwell B scale.
No Of Hours
Rockwell Hardness
2
22.5
4
38
6
55.5
8
68.5
10
72
12
74
14
76
16
79
18
82
20
84
22
86
24
86
26
86
28
86
Rockwell hardness reference to time.
values
with
Hardness vs. Time.
CONCLUSIONS
1.
The crystallite size of the silicon carbide powder was reduced from 197 nano meters to the 58 nano meters.
2. The Rockwell B scale hardness values are increasing with the homogenizing time. 3. The values of hardness are initially 22.5 and after homogenizing it for 28 hours in the muffle furnace.The final value is reached up to 86. 4. the hardness values improved .
THANK YOU
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