A rare work on the forming of nano cast iron, characterization and hardness measurement. Nano carbon is used in small increments as additions.

1. Forming, Characterization and Evaluation of
Hardness of NanoCarbon Cast Iron
By
SAI SIRISHA K
M.TECH CAD/CAM
Guide:
Dr. K.Padmanabhan (SMBS)
VIT University, Vellore

2. Outline of the presentation
 Abstract
 Introduction
 Experimental procedure
 Principles of each step
 Results and Discussion
 Conclusion
 References

4. • Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical
nanostructure.
• Nanotubes have been constructed with length-to-diameter ratio of up to
132,000,000:1,significantly longer than any other material.
• These cylindrical carbon nano tubes have unusual properties, which are
valuable for structural, electronics, optics and other fields of material
science and technology.

5. Properties of carbon nano tubes:
o The strongest and most flexible molecular material because
of C-C covalent bonding.
o Carbon nanotubes are the strongest and stiffest materials yet discovered in terms
of tensile strength and elastic modulus respectively
o High Hardness
o Less dislocations
o Tensile strength – 63gpa-200gpa
o Youngs modulus – 1tpa
o Low density of a solid

6. Classification of CNT:
 Single walled carbon nano tubes(SWCNT)
 Multi walled carbon nano tubes(MWCNT)
SWCNT MWCNT

7. Cast iron reinforced with nano-sized carbon(mwcnt) particles are an
interesting group of advanced materials.
The composites possesses improved physical and mechanical
properties such as
 superior strength to weight ratio,
 good ductility ,
 high strength and high modulus
 low thermal expansion coefficient,
 excellent wear resistance,
 excellent corrosion resistance
 high temperature creep resistance and
 better fatigue strength.

8. EXPERIMENTAL PROCEDURE:
•Characterization of MWCNT
•Forming and Characterization of Nano Carbon Cast Iron.
•Heat Treatment and Machining
•Hardness Testing Procedure

9. I. Characterization of MWCNT
SPECIFICATIONS:
Make : BRUKER, Germany
Model : D8 Advance
Source : 2.2KW Cu anode,
ceramic x-ray tube
Detector : lynx Eye detector(silicon
strip detector technology)
Beta Filter : Ni Filter
Sample Holder : Zero background and
PMMA sample holder
sample
liq N2
detector
X-ray
source
 
Geometry of XDS 2000

10. Observations made in XRD;
Graph between Intensity and 2-Theta scale for MWCNT

11. Surface topography of the MWCNT:
Principle of AFM
Between the nano-scale tip and the atoms of the
surface is picked up by changes in the laser beam
reflection and converted by a computer
into a picture.
Deflection of the cantilever due to varying
forces

12. Observations are made in AFM:

14. a) Copper Coating and stir casting:
Why Copper coating?
 It prevents clustering of carbon nanotubes (agglomeration)
 Cu is good for corrosion resistance and it prevents reactivity between carbon
and iron which improves the strength, stiffness of castiron.
 Cu forms an oxide thereby reducing reactivity between iron and carbon
Why stir casting?
 Distribution of MWCNT will be good in castiron
II Forming and Characterization of Nano Carbon Cast Iron:

15. Elements for stir casting:
FurnaceBlower Charcoal Coke
Crucible MWCNT Cast iron Copper

16. Working of stir casting:

17. Patterns for test specimens:
Mould preparation for test specimens:

18. After pouring the molten metal into moulds:
Raw castings thus formed are then
withdrawn from the moulds

19. III Heat Treatment and Machining
Dimension for tensile test specimen
Tensile test specimen being machined on lathe

20. A machined test specimen of NCCI
IV Hardness Testing Procedure:
• Rockwell hardness C test ( HRC) is used to calculate the hardness
number of a ferrous material.
•It consists of indenting the test material with a diamond cone or
hardened steel ball indenter
•All the six specimens, heat treated and as cast, were hardness
tested and the hardness values were recorded.

21. Results and Discussions
o XRD:
Diffraction peaks will perform in the deflection pattern at 2 ѳ values when
Constructive interference is at a maximum that is braggs law is satisfied .
The number of observed peaks is connected to the symmetry of the unit cell.
The d-spacings of the observed peaks are related to the restating distances
among planes of atoms in the structure. Here in this XRD graph peaks are
observed at (d=3.47092,A=25.6450) and (d=2.08297,A=43.4080)
X Ray diffraction pattern of as cast X Ray diffraction pattern of heat treated and
NCCI showing undissolved impurities annealed NCCI Samples

22. o AFM:
With using AFM the image of the multi walled carbon nano tubes is noticed with
different orientations clearly and the dimensions like length, depth, area roughness
i.e area are observed and shown in table 1 and table 2
o Very hard and strong castirons are obtained
o Microstructure of NCCI:
The optical microstructure of grey cast Micrograph of as cast NCCI showing fair
iron before the addition of MWCNT. distribution of the MWCNT cluster.

23. Micrograph of a region in a heat treated Another region of the heat treated
and annealed NCCI and annealed NCCI
Observations of Hardness in the NCCI:
S No Hardness Number
1 25
2 21
3 22
S No Hardness Number
1 17
2 19
3 17
HRC of as cast NCCI HRC of Annealed NCCI

24. Conclusions:
Forming of MWCNT nano carbon reinforced cast iron with the stir casting method
was carried out.
The x-ray diffraction, microscopic characterization and measurement of Rockwell C scale
hardness before and after heat treatment (of the Nano Carbon Cast Iron or NCCI ) were also
conducted.
X- Ray and Atom Force Microscope (AFM) characterization were carried out for the
multi walled carbon nano tube reinforcements as well as the nano carbon cast iron formed
by adding the nano carbon with the grey cast iron.
As the nano carbon reinforcements tend to agglomerate in the cast iron eutectic melt,
prior sonication and coating with copper were done to prevent agglomeration, dissolution
and oxidation of nano carbon .
The as cast samples were either cooled naturally or heat treated at 550 ºC and annealed,
machined down to size and the Rockwell C scale hardness measured.
 The annealed samples show reduced hardness values compared to as cast samples
due to the formation of α-ferrite. They also exhibited less porosity and a low tendency
for graphitization.

25. References:
[1] PM Ajayan and S Iijima, Smallest carbon nanotube, Nature, 358(6381), (1992) pp23-23.
[2] TW Ebbesen and PM Ajayan, Large scale synthesis of carbon nanotubes, Nature, 358(6383),
(1992) pp 220-222, .
[3] Sidney H Avner, Inroduction to Physical Metallurgy, Second Edition, Tata McGraw-Hill Edition, (1997)
p231 .
[4] F.Foroozmehra, A.Najafizadehb and A. Shafyeib, Effects of carbon content on the formation of
nano/ultrafine grained low-carbon steel treated by martensite process, Materials science and engineering
A, 528, (2011) pp 5754-5758.
[5] N.Tsuji, R.Ueji, Y.Minamino and Y.Saito, A new and simple process to obtain nano-structured
bulk low-carbon steel with superior mechanical property , Scripta Materialia, 46 (4), (2002) pp305-310
[6] X Ray Diffractometer, Model D8 Advanced, Manual, Bruker, Germany, 2006.

26. [7] ASM International, Heat treater’s guide : practices and procedures for irons and
steels, ASM International handbook, Metals Park, Ohio, (2007) .
[8] SR Williams, Hardness and Hardness Measurement- A Report, American Society for
Metals, Metals Park, Ohio, (1942).
[9] Tasgin Y, Kaplan M, Yaz M, Investigation of effects of boron additives and heat
treatment on carbides and phase transition of highly alloyed duplex cast iron, Materials
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[10] CA Bixler, KL Hayrynen, J Keough, G Pfaffmann and S Gledhill, Locally
Austempered Ductile Iron, SAE International Journal of Materials and Manufacturing,
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27. Any Queries