DEVELOPMENT OF ALUMINIUM BASED SILICON CARBIDE AND...

DEVELOPMENT OF ALUMINIUM BASED SILICON CARBIDE AND CNT

PARTICULATE METAL MATRIX COMPOSITE (MMC) FOR SPUR GEAR

A.PANDIANATHAN [email protected]

Department of mechanical engineering, M.I.E.T Engineering College, Trichy, India.

S.KUMARADEVAN [email protected]

Department of Mechanical Engineering, M.I.E.T Engineering College,

Trichy, India

Abstract— MMCs are made by dispersing a reinforcing material into a metal matrix. They are prepared by powder metallurgy and casting, although several technical challenges exist with casting technology. Achieving a homogeneous distribution of reinforcement within the matrix is one such challenge, and this affects directly on the properties and quality of composites. The aluminium alloy composite materials consist of high strength, high stiffness, more thermal stability, more corrosion and wear resistance, and more fatigue life. Aluminium alloy materials found to be the best alternative with its unique capacity of designing the materials to give required properties. In this work, a composite is developed by adding silicon carbide and carbon nanotubes in Aluminium metal by mass ratio 2.5%, 5%, 7.5% and 10%. The composite is prepared by stir casting technique. Mechanical tests such as hardness test, microstructure test, and SEM test are conducted. It is proposed to use this material for power transmitting elements such as Spur gears which are subjected to continuous loading. Finally modelling and finite element analysis of gear is done using CATIA and ANSYS 15.0. In case of increased silicon carbide content, the hardness, and material toughness are enhanced. From the results it is concluded that composite material such as aluminium silicon carbide is one of the option as a material for power transmission gears. Keywords— Metal matrix, Carbon nano tubes, Ceramics, Composites. Introduction

Metal matrix composites are broadly used in aerospace, automobile, marine and structural application, etc., due to its outstanding mechanical properties. Metal matrix composite stands for reinforcement in a ductile metal matrix. Strength of MMC is considerable better than the strength of base metal. The super alloys and alloy of Al, Mg, Ti and Cu were working as metal matrix material. The reinforcement can be in the form of particles, continuous and discontinuous fibers. These MMC’s are very expensive, but many advantage over polymer matrix composite such as higher operating temperature, non- flammability and more resistance to degradation of organic fluids. Aluminum metal matrix composites (Al-MMCs or AMCs) are materials in which reinforcement, typically a ceramic-based material, is added with the purpose of improving the materials properties. In AMCs one of the constituent is aluminum/aluminum alloy, percolating network and is termed as matrix phase. The other constituent is embedded in this aluminum alloy matrix and serves as reinforcement, which is usually non-metallic and commonly ceramic such as SiCandAl2O3 .Properties of AMCs can be tailored by varying the nature of constituents and their volume fraction. Tribological behavior is an important aspect in the use of aluminum metal matrix composites in automotive applications. The wear behavior of Al-Si alloys can be further enhanced by adding ceramic particles. Abrasive particles like silicon carbide, alumina, and diamond are added to improve the tribological behavior by increasing the hardness of a composite.

International Journal of Research

Volume 7, Issue V, MAY/2018

ISSN NO : 2236-6124

Page No:411

Metal Matrix composites(MMC’s)

Al 6063 was used as the matrix, alumina as hard reinforcement and molybdenum disulfide as soft reinforcement. It has very good cast ability. The properties of the composites were measured as Density 2.7 g/cm3, Poisson Ratio 0.33, Melting Point 580°, Modulus of Elasticity 70-80 GPa. Silicon Carbide is the only chemical compound of carbon and silicon. Silicon carbide is an excellent abrasive with very good mechanical properties such as low density, high strength, high thermal conductivity, high hardness, high elastic modulus and excellent thermal shock resistance. Carbon nano tubes are large molecules of pure carbon that are long and thin shaped like tubes, about 13 nanometers (1 nm = 1 billionth of a meter) in diameter, and hundreds to thousands of nanometers long. As individual molecules, nano tubes are 100 times stronger than steel and one sixth its weight. Here we have been adopted the stir casting method for the preparation of ALSIC in metal matrix composites. In this investigation, four self-lubricating composites of molybdenum disulphide, namely, Al 6063 / 3% MoS2 / 10% Al2O3, Al 6063 / 5% MoS2 / 10% Al2O3, Al 6063 / 7% MoS2 / 10% Al2O3 and Al 6063 /9% MoS2 / 10% Al2O3 have been produced with the stir-casting route. The changes in the mechanical and tribological properties caused by the addition of MoS2 are studied. This whirlpool technique provides the high strength homogeneous set of aluminum composite materials.

The aim of the research is to emphasize the production of Metal matrix Al-Sic and CNT composite using the stir casting method and prepare four samples of varying percentiles of Sic 50%,75%,100% and 125%,and CNT 10%,20%,30%,40% with aluminium.

Experimental Analysis:

Brinell Hardness Testing: All Brinell tests use a carbide ball indenter. The indenter is pressed into the sample by an accurately controlled test force. The force is maintained for a specific dwell time, normally 10 - 15 seconds. After the dwell time is complete, the indenter is removed leaving a round indent in the sample. The size of the indent is determined optically by measuring two diagonals of the round indent using either a portable microscope or one that is integrated with the load application device. The Brinell hardness number is a function of the test force divided by the curved surface area of the indent. The indentation is considered to be spherical with a radius equal to half the diameter of the ball. The average of the two diagonals is used in the following formula to calculate the Brinell hardness. Load P= 250N, Steel ball diameter D=5mm, Depression diameter d=2.6mm

BHN=4.451

BASE ALIMINIUM

R1 SILICON CARBIDE

(grams)

R2 CARBON

NANO TUBES (grams)

1kg 50 10

1kg 75 20

1kg 100 30

1kg 125 40



ISSN NO : 2236-6124

Page No:412

Vickers Hardness Testing:

The Vickers hardness test method consists of indenting the test material with a diamond indenter, in the form of a pyramid with a square base and an angle of 136 degrees between opposite faces subjected to a test force of between 1gf and 100kgf. The full load is normally applied for 10 to 15 seconds. The two diagonals of the indentation left in the surface of the material after removal of the load are measured using a microscope and their average calculated. The area of the sloping surfaces of the indentation is calculated. The Vickers hardness is the quotient obtained by dividing the kgf load by the square mm area of indentation. The unit of hardness given by the test is known as the Vickers Pyramid Number (HV) or Diamond Pyramid Hardness (DPH)

250 200 150 100 50 0 Specimen 1 specimen 2 specimen 3 specimen 4

Vickers hardness testing

--- Impact Tests

Impact tests are designed to measure the resistance to failure of a material to a suddenly applied force. The test measures the impact energy, or the energy absorbed prior to fracture. The most common methods of measuring impact energy are the:

(i) Charpy Test (ii) Izod Test The charpy test:

While most commonly used on metals, it is also used on polymers, ceramics and composites. The Charpy test is most commonly used to evaluate the relative toughness or impact toughness of materials and as such is often used in quality control applications where it is a fast and economical test. It is used more as a comparative test rather than a definitive test. Charpy test specimens normally measure 55x10x10mm and have a notch machined across one of the larger faces. The Charpy test involves striking a suitable test piece with a striker, mounted at the end of a pendulum. The test piece is fixed in place at both ends and the striker impacts the test piece immediately behind a machined notch. At the point of impact, the striker has a known

amount of kinetic energy. The impact energy is calculated based on the height to which the striker

NO.OF SPECIMENS

BRINELL HARDNESS NUMBER

1 4.451

2 4.099

3 4.451

4 4.099

IDENTIFICATION

IMPACT VALUE IN

JOULES

Specimen 1 7

Specimen 2 6

Specimen 3 7

Specimen 4 8



ISSN NO : 2236-6124

Page No:413

would have risen, if no test specimen was in place, and this compared to the height to which the striker actually rises. Tough materials absorb a lot of energy, whilst brittle materials tend to absorb very little energy prior to fracture.

Optical microscope The optical microscope, often referred to as

light microscope, is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were possibly invented in their present compound form in the 17th century. Basic optical microscopes can be very simple, although there are many complex designs which aim to improve resolution and sample contrast. The image from an optical microscope can be captured by normal light-sensitive cameras to generate a micrograph. Originally images were captured by photographic film but modern developments in CMOS and charge-coupled device (CCD) cameras allow the capture of digital images. Purely digital microscopes are now available which use a CCD camera to examine a sample, showing the resulting image directly on a computer screen without the need for eyepieces.

Sem Test A scanning electron microscope

(SEM) is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the sample's surface topography and composition. The electron beam is generally scanned in a raster scan pattern, and the beam's position is combined with the detected signal to produce an image. SEM can achieve resolution better than 1 nano meter. Specimens can be observed in high vacuum, in low vacuum, in wet conditions (in environmental SEM), and at a wide range of cryogenic or elevated temperatures. The most common SEM mode is detection of secondary electrons emitted by atoms excited by the electron beam. The number of secondary electrons that can be detected depends, among other things, on specimen topography. By scanning the sample and collecting the secondary electrons that are emitted using a special detector, an image displaying the topography of the surface is created.

In a typical SEM, an electron beam is thermionically emitted from an electron gun fitted with a tungsten filament cathode. Tungsten is normally used in thermionic electron guns because it has the highest melting point and lowest vapour pressure of all metals, thereby allowing it to be electrically heated for electron emission, and because of its low cost. Other types of electron emitters include lanthanum hexa boride cathodes, which can be used in a standard tungsten filament SEM if the vacuum system is upgraded or field emission guns (FEG), which may be of the cold-cathode type using tungsten single crystal emitters or the thermally assisted Schottky type, that use emitters of zirconium oxide.

The electron beam, which typically has an energy ranging from 0.2 keV to 40 keV, is focused by one or two condenser lenses to a spot about 0.4 nm to 5 nm in diameter. The beam passes through pairs of scanning coils or pairs of deflector plates in the electron column, typically in the final lens, which deflect the beam in the x and y axes so that it scans in



ISSN NO : 2236-6124

Page No:414

a raster fashion over a rectangular area of the sample surface.

Design of Spur Gear

Lewis formula and Hertz Equation are derived to account for various factors which

have influence on gear rating. Gear design engineering is not an exact science; it is a mixture of art and science. There are two theoretical formulas, which deal with the design of gear, one is the Hertz equation, which can be used to calculate the contact stresses and other

Gear pair is designed by using Lewis formula (i.e. for bending Strength) for transmitting 10kW power at 1440 rpm input speed. Following are the inputs taken for designing gear pair. Finite element modelling is described as the representation of the geometric model in terms of a finite number of element and nodes. It is actually a numerical method employed for the solution of structures or a complex region defining a continuum. This is an alternative to analytical methods that are used for getting exact solution of analysis problems. The solution of general problem by finite element method always follows an orderly step-by-step process for analysis in ANSYS 14.0. The loading conditions are assumed to be static. The element chosen is solid Brick 8 node 45. After gear design has done by using Lewis equation for bending strength next step will be modelling of gear and Finite Element Analysis. The Young’s Modulus for composite is calculated theoretically using the formula mentioned by Chabra et al. Fig. Shows Stress and equivalent strain distribution on gear teeth. It can be clearly seen from these figures that maximum stress value is obtained at the tip of teeth, which is in conformation with assumption made in Lewis theory.

Module (m)

5mm

Addendum 5mm

Dedendum

6.25mm

Pressure angle (α) 20

Tooth thickness (t)

7.85mm

Whole depth

11.25mm

Face width (b)

27mm

Fillet radius

2mm

No of teeth (z)

18

Pitch circle diameter

90mm

Tip circle diameter

100mm

Circular pitch 15.70mm



ISSN NO : 2236-6124

Page No:415

Analysis of spur gear made on AL-sic and CNT (a) stress distribution

STRAIN DISTRIBUTION

Conclusion

Silicon carbide particle reinforced aluminium matrix composite (AMCs) were prepared by stir-casting with different particle weight fraction (1:50:10) the following conclusions can be drawn:

(i) Hardness of Al-Sic is much better than the aluminium metal. In case of increased silicon carbide

content. The hardness and material toughness are enhanced and highest value is obtained at (1:50:10) SiC and CNT content.

(ii) More uniform distribution of SiC particles can be found if composite is prepared by powder metallurgy,and then stir casting; however stir casting is more economical.

(iii) These composites can be used for making power transmitting elements such as gears, which are subjected to continuous loading.

(iv) Distribution obtained in FEA analysis shows highest stress value at tip of the teeth, and strain value is comparatively lower.

References

Behera Rabindra, S.Kayal, Mohanta N.R., G.Sutradhar, 2013 ―Study on Machinability of Aluminium Silicon Carbide Metal Matrix Composites” Transactions of 61st Indian Foundry Congress.

Chabra Pankaj , Bhatia Amit , 2012 ―Design and Analysis of Composite Material Gear Box‖, International Journal of Mechanical and Civil Engineering, Vol.1, Issue1, pp 15-25

Chawathe D.D., 2001 ―Handbook of Gear Technology‖, New Age International Publication, pp 26-89,305-536, 579-706

Devi Neelima, Mahesh.V, Selvaraj. N, 2011 ―Mechanical characterization of Aluminium silicon carbide composite‖, International Journal Of nApplied Engineering Research, Volume 1, Issue 4, pp 793-799

Dunia Abdul Saheb, 2011 ―Aluminium Silicon Carbide and Aluminium Graphite Particulate Composites‖, ARPN Journal of Engineering and Applied Sciences, VOL. 6, Issue 10, pp 41-46

Gulaxea Pratik, Awate N.P., 2013 ―Design, Modeling & Analysis of Gear Box for Material Handling Trolley: A Review‖, Mechanical Confab, Vol. 2, Issue1, pp 63-70.



ISSN NO : 2236-6124

Page No:416



ISSN NO : 2236-6124

Page No:417

DEVELOPMENT OF ALUMINIUM BASED SILICON CARBIDE AND...

Documents

Transcript of DEVELOPMENT OF ALUMINIUM BASED SILICON CARBIDE AND...