Aluminium Kyanite Composite New

7/27/2019 Aluminium Kyanite Composite New

1/64

PRESENTED BY :BALAJI . V,USN 1GC10MSE034TH SEM M-TECH

UNDER THE GUIDANCE OF :

DR.A.R.ANWAR KHAN

PROF & HEAD

DEPARTMENT OF MECHANICAL

ENGG.


2/64

INTRODUCTION

LITERATURE SURVEY

SCOPE OF PRESENT INVESTIGATION

EXPERIMENTAL PROCEDURE

RESULTS AND DISCUSSIONS

CONCLUSION

SCOPE FOR FUTURE STUDY


3/64


4/64

Composite materials are defined as material systems

consisting of mixture or combination of two or more micro

constituents insoluble in each other and differing in form and or

material composition.


5/64

Modern Technologies require materials with unusual combination of

properties that cannot be met by the conventional metal alloys, Ceramics, and

polymeric materials that are needed for aerospace, underwater and transportation

applications.

For example, aircraft engineers are increasingly searching for structuralmaterials that have low densities, strong, stiff , abrasion, impact resistant and not

easily corroded.

Some of the properties that can be improved by forming a composite material

are Strength, Stiffness, Corrosion and wear resistance, Weight Reduction, Fatigue life,

Temperature dependent behavior, Thermal properties, Electrical properties.


6/64

Composite Material consists of

1. Matrix binder

Matrix is a material, which binds the filler and holds it. Any solid can

be processed so as to embed and adherently grip a reinforcing phase in a

potential matrix material.Ex: Polymer Matrix, Ceramic Matrix, Metal Matrix

2. Reinforcing filler

Reinforcing constituents in composites, as the word indicates, provide

the strength that makes the composite what it is. But they also serve certain

additional purposes of heat resistance or conduction, resistance to corrosion

and provide rigidity.

Ex: Fibers, Whiskers, Platelets and Flakes, Particulate


7/64

1. Fiber Reinforced Composites:Fiber Reinforced Composites are composed of fibers embedded in matrixmaterial. Such a composite is considered to be a discontinuous fiber or short

fiber composite if its properties vary with fiber length.

2. Laminar Reinforced Composites:

Laminar Composites are composed of layers of materials held together bymatrix. They can be described as materials comprising of layers of materials

bonded together. These may be of several layers of two or more metal materials

occurring alternately or in a determined order more than once, and in as many

numbers as required for a specific purpose. Sandwich structures fall under this

category.3. Particulate Reinforced Composites:

Particulate Composites are composed of particles distributed or embedded

in a matrix body. The particles may be flakes or in powder form. Concrete and

wood particle boards are examples of this category.


8/64

Aerospace and Defence

MMCs based on Al and Ti matrix are currently being used / evaluated for a variety of

engine components. One of the successful application is Al MMC Fan Exit Vane (FEGV) in

the gas turbine.

Al 6061 MMCs are used for End closure, Nozzle retainer and Engine body tube in the

Tempest sounding Rocket.

Automotive Applications

Brake Discs / brake Drums

Substitution of cast iron brake discs by Al MMC brake discs (in cars and

railways) will increase vehicle dynamics and acceleration. Benefits occurred include 50%

weight savings in braking system, less noise, superior thermal dissipation, improved

mileage and improved life cycle economy

Cylinder liners

Al MMC liners reinforced with a mixture of Al2O3 particles and graphite and

integrally cast have been developed by Honda Motor Company of Japan. Engine block with

Al MMC liners weighs only 50% of cast iron block, has also improved efficiency andwears resistance. Contd.


9/64

Push Rods

Similarly, automotive push rods of AL MMCs have been

developed for racing cars engines. These push rods weigh only 40% of

their steel counter parts, and stronger and stiffer.

In addition to the above applications, MMCs are used in tennis

rackets, skis and golf clubs, bicycle frames and yacht masts.


10/64

High resistance to fatigue and corrosion degradation.High strength or stiffness to weight ratio.

Due to greater reliability, there are fewer inspections and structural repairs.

Improved dent resistance is normally achieved. Composite panels do not sustain

damage as easily as thin gage sheet metals.

High resistance to impact damage.Composites are dimensionally stable i.e. they have low thermal conductivity and

low coefficient of thermal expansion.

Manufacture and assembly are simplified because of part integration (joint/fasten

reduction) thereby reducing cost.

The improved weatherability of composites in a marine environment as well astheir corrosion resistance and durability reduce the down time for maintenance.

Close tolerances can be achieved without machining.

Excellent heat sink properties of composites.

Improved friction and wear properties.


11/64

High cost of raw materials and fabrication.

Composites are more brittle than wrought metals and thus are more

easily damaged.

Transverse properties may be weak.

Matrix is weak, therefore, low toughness.

Reuse and disposal may be difficult.

Poor public acceptance.


12/64


13/64

Aluminium is the third most abundant element

(after oxygen and silicon), and the most abundant metal,

in the Earths crust. It makes up about 8% by weight of

the Earth's solid surface. Aluminium metal is too reactivechemically to occur natively. Instead, it is found combined

in over 270 different minerals. The chief ore of aluminium

is bauxite.

Aluminium is remarkable for the metal's lowdensity and for its ability to resist corrosion due to the

phenomenon of passivation.


14/64

Density 2.7 g.cm-3 at 20C

Melting Point 660.4C

Boiling Point 2647C


15/64

A silvery and ductile member of the poor metalgroup of elements, aluminium is found primarily asthe ore bauxite and is remarkable for its resistanceto oxidation.

In automobiles of all modern mirrors are madeusing a thin reflective coating of aluminium on the

back surface of a sheet of float glass.

Telescope mirrors are also coated with a thin layerof aluminium.

The other applications are like electricaltransmission lines, and packaging (cans, foil, etc.).


16/64

Kyanite is an alumino silicate mineral withthe chemical formula Al2SiO5 whose namederives from the Greek word kuanos sometimes

referred to as "kyanos", meaning deep blue, is atypically blue silicate mineral, commonlyfound in aluminium-rich metamorphicpegmatites and/or sedimentary rock.


17/64

Properties

Density 3.53 3.67gm/cm3

Melting point 1350C it converts into mullite andfree silica

Mullite imparts highly desirablerefractory properties of greatstrength and is stable upto 1810C

Solublility Soluble in water at 700C


18/64


19/64

Mullite, a form of calcined kyanite, is used to make

brake shoes and clutch facings.

Use in High Refractory Strength Porcelain

Kyanite has properties that make it exceptionally

well suited for the manufacture of a high refractory-

strength porcelain - a porcelain that holds its

strength at very high temperatures. A familiar use ofthis type of porcelain is the white porcelain insulator

on a spark plug.

Fig : The porcelain insulator on this spark

plug was made with kyanite.

Contd..


20/64

Use in Abrasive Products

Kyanite's heat resistance and hardness makes it an

excellent material for use in the manufacture of

grinding wheels and cutting wheels. It is not used as

the primary abrasive, instead it is used as part of the

binding agent that holds the abrasive particles

together in the shape of a wheel.

Fig: Kyanite is used as a heat resistant

binding medium in cutting tools and

grinding wheels.


21/64


22/64


23/64

Kyanite has been chosen as the reinforcement as it posses

high melting-point and excellent refractory properties.

As the kyanite is used in high temperature applications such

as porcelain insulator on the spark plug, in the manufactureof refractory products such as the bricks, mortars and kiln

furniture used in high temperature furnaces, it can resist

thermal distortion.

The combination of aluminiumkyanite composites ischosen to prepare the parts to improve mechanical

properties, weight loss, corrosion resistance along with

resistance to thermal distortion. This replaces the parts that

fails because of high temperature applications such asAluminium heat exchanger, aluminium capacitors,

aluminium pans, heat sinks, wires etc.


24/64

Cast aluminium and kyanite composites have been

produced by liquid metallurgy route which is a very popular

technique owing to its economy and versatility coupled with

large-scale production. The extent of incorporation of kyanite (Al2SiO5) in the

matrix alloy has been tried out from base matrix, 3%, 5%

and 7%.

Microstructure studies, hardness, tensile tests, SEM study,wear test, corrosion test have conducted on the base matrix

and composites.


25/64

Aluminium Kyanite

Castings byVortex method

Metallicmould

Coal FiredPit Furnace

Composites prepared with varied percentage as 3%, 5% & 7% of Kyanite

Characterization

Micro-structure

HardnessCorrosion

testWear testTensile test

SEM Study


26/64


27/64


28/64

Reinforcement :

Kyanite(Al2SiO5) was chosen as reinforcement owing to

its high melting-point and excellent refractory properties.

Fig: Kyanite powder

Kyanite powder of particle size 16 - 30m procured from

Navbhan Exporters, Bangalore at Rs 10/kg have been used in

the present work.

Table : Chemical composition of Kyanite

Elements Al2O3 SiO2 TiO2 Fe2O3wt % 50.0 - 55.0 39.0 - 45.0 0.5- 0.6 0.80 -1.75


29/64


30/64

Coke-Fired Furnace.

Primarily used for non-ferrous metals

Furnace is of a cylindrical shape

Also known as pit furnace

Preparation involves: first to make a deep bed of coke in the

furnace

Burn the coke till it attains the state of maximum combustion

Insert the crucible in the coke bed

Remove the crucible when the melt reaches to desired

temperature

Fig. Coke-Fired Furnace.


31/64

The method adopted for preparation of composite was liquid

metallurgy route. The matrix aluminium was heated and melted in a graphite

crucible using an coke fired pit furnace. The maximum

temperature limit is 20000C.

Degassing is achieved by Hexachloroethane tablet whichwere immersed into molten metal before stirring. Coverall

powder will be used to avoid oxidation.

Ceramiccoated impeller was immersed gently into the

molten metal bath and rotated at a speed of 250 to 300 rpm

to create the vortex. Pre heated kyanite Al2SiO5 was added

slowly in the vortex of molten metal.

I d t t if di t ib ti f Al2SiO5 ti l th


32/64

In order to get uniform distribution of Al2SiO5 particles, the

composites was stirred continuously for duration of 10

minutes.

The composites melt was then poured into preheated metal

mould (Fig. 5.5) using ladle.

Fig. Metallic Moulds Fig. Cast Composite Specimens

Al and its composites with reinforcement of 3%, 5% and 7%

by weight is added and the specimens of 28mm diameter and

200mm long have been successfully casted.


33/64

Micro-Structure

Hardness

Tensile test

Wear test

Corrosion test

SEM study on fractured tensile specimens


34/64


35/64


36/64


37/64

The definition of wear may include loss of dimension from plastic

deformation which is originated at the interface between two sliding

surfaces.

The wear test is performed on Pin On Disc Tester TR-20LE.

Fig. Pin On Disc Tester


38/64

The corrodants used were different concentrations of NaCl, equimolar


39/64

, q

solution of NaCl and natural sea water.

The corrosion tests were conducted using conventional weight loss

method on all types of specimens and the exposure time was varied from

24 to 96 hours, in steps of 24 hours.

The cradles containing the weighed specimens were kept inside the flask

containing the corrodant. A ratio of 50 ml to 1 mm2 of surface area was

maintained according to ASTM standards.

To minimize the contamination of the aqueous solution and loss due to

evaporation, the flasks were covered with paraffin during the entire test

period.

After the corrosion test, the specimens were immersed in acetone solution

for 10 minutes and gently cleaned with a soft brush to remove adhered

scales.

After drying thoroughly, the specimens were reweighed to determine thepercentage weight loss, weight loss per unit area of exposure and

corrosion rate in mpy.

Corrosion rate was calculated using the formula,

Corrosion rate = 534 W/AT mpy,

where W is the weight loss in grams, is density of the specimen (g cm-3

), A is the area of the specimen(inch) and T is the exposure time in hours.


40/64

The scanning electron microscope (SEM) uses a focused beam of high-

energy electrons to generate a variety of signals at the surface of solidspecimens. The signals that derive from electron-sample interactions

reveal information about the sample including external morphology

(texture), chemical composition, and crystalline structure and orientation

of materials making up the sample.

The fractured tensile specimens is captured on JEOL JSM-840A

Scanning Electron Microscope.


41/64


42/64


43/64

SAMPLE 2

Diameterd (mm) Lengthl (mm) BreakingStress

(MPa)

Yield Stress(MPa)

Ultimate TensileStrength (MPa)

Elongation(%)

62.5 12.49 73.45 73.45 80.95 8.75

Sample Hardness(HBW)1 43.6

COMPOSITION :Aluminium + 3% Kyanite

TENSILE TEST HARDNESS TEST

WEAR TEST

Load 2 Kg( 19.62 N)

900 Sec

4 Kg( 39.24N)

389 Sec

6 Kg( 58.86 N)

335 Sec

Wear (m) 89 1322 305

CO-EFFICIENT OF FRICTION

Load 2 Kg( 19.62 N) 4 Kg( 39.24N) 6 Kg( 58.86 N)

Co-efficient

of Friction

0.43 0.9 0.48

Time in

Hour

Corrosion

Rate (mpy)

240.0136

480.0086

72 0.0044

96 0.0042

CORROSIONTESTSEM PHOTOGRAPHMICROSTRUCTURE


44/64


45/64


46/64

Specimen Composites Average Hardness(HBW)

Sample 1 Base Matrix 44.2Sample 2 3% Kyanite 43.6Sample 3 5% Kyanite 41.8Sample 4 7% Kyanite 43.4

From the figure & table it is observed that sample 2, 3 & 4 are having less

hardness of 1 to 3% when compared with Base matrix.

There is a good reason for this phenomenon, since kyanite being a soft

dispersoid, it does not contribute positively to the hardness of the composite. Such a

monotonic decrease in the hardness of the composite as kyanite content isincreased poses a limit to how much kyanite may be added to enhance its other

mechanical properties.

Since hardness is directly related to wear resistance, a compromise is

necessary when deciding how much kyanite should be added to enhance the

ductility, UTS, compressive strength, and Young's modulus of the composite without

sacrificing too much of its hardness.


47/64

Specimen Composites Breaking Stress(MPa)

Sample 1 Base Matrix 48.66Sample 2 3% Kyanite 73.45Sample 3 5% Kyanite 53.04Sample 4 7% Kyanite 53.8

From the figure & table it is observed that sample 2 requires more load to break

the specimen. This is due to the presence of less % of Kyanite & also has very low hardness.

Increased content of reinforcement results in enhanced breaking load of composites

for a given reinforcement content. Composites with kyanite reinforcement possess higher

breaking load when compared with base matrix. Al - 3% kyanite composite posses a higherbreaking stress of 34% when compared with Base matrix.


48/64

Specimen Composites Yield Stress(MPa)Sample 1 Base Matrix 68.76Sample 2 3% Kyanite 73.45Sample 3 5% Kyanite 83.95Sample 4 7% Kyanite 83.97

From the figure & table it is observed that sample 3 & 4 requires more load

to yield the specimen.

Increased content of reinforcement results in enhanced yield load of

composites for a given reinforcement content. Composites with kyanite

reinforcement possess higher yielding load when compared with base matrix. Al with5% & 7% kyanite composite posses a higher yielding stress of 18% when compared

with Base matrix.


49/64


50/64

Specimen Composites Elongation(%)Sample 1 Base Matrix 8.45Sample 2 3% Kyanite 8.75Sample 3 5% Kyanite 13.71Sample 4 7% Kyanite 19.7

From the figure & table it is observed that sample 4 are having more

Elongation. Increased content of reinforcement results in enhanced elongation of

specimen for a given reinforcement content. Al with 7% kyanite composite posses a

higher elongation of 11% when compared with Base matrix.


51/64

Specimen Composites Wear (m)Sample 1 Base Matrix 94Sample 2 3% Kyanite 89Sample 3 5% Kyanite 112Sample 4 7% Kyanite 73

From the figure & table it is observed that sample 2 & 4 are having less

wear.Increased content of reinforcement results in enhanced resistance to wear

of composites for a given reinforcement content. Composites with kyanite

reinforcement possess higher wear resistance except in sample 3 when compared

with base matrix. Al with 7% kyanite composite posses a higher wear resistance of

22% under 2 kg load when compared with Base matrix.

Wear test under 2 kg (19.62N) load (Time900 Sec, Speed600

rpm, Track dia80mm)


52/64


Wear test under 4 kg (39.24N) load (Time 389 Sec, Speed

600 rpm, Track dia 80mm)

From the figure & table it is observed that sample 2, 3 & 4 are having less wear

when compared to base matrix.

Increased content of reinforcement results in enhanced resistance to

wear of composites for a given reinforcement content under 4 kg load.

Composites with kyanite reinforcement possess higher wear resistance when

compared with base matrix. Al with 5% kyanite composite posses a higher wear

resistance of 56% under 4 kg load when compared with Base matrix.


53/64


From the figure & table it is observed that sample 2 & 5 are having less

wear. Increased content of reinforcement results in enhanced resistance to wear ofcomposites for a given reinforcement content. Composites with kyanite

reinforcement possess higher wear resistance except in sample 4 when compared

with base matrix. Al with 3% kyanite composite posses a higher wear resistance of

82% under 6 kg load when compared with Base matrix.

Wear test under 6 kg (58.86N) load (Time 335 Sec, Speed

600 rpm, Track dia 80mm)


54/64


55/64

Specimen Composites Co-efficient of FrictionSample 1 Base Matrix 0.81Sample 2 3% Kyanite 0.9Sample 3 5% Kyanite 0.34Sample 4 7% Kyanite 0.7

Fig. shows the relationship between Co-efficient of Friction and % of

Al2SiO5 addition under 4 kg load. It can be seen that, Specimen 2 showed muchhigher coefficient of friction 0.9. Specimen 3 showed lower coefficient of friction 0.34.

Co-efficient of Friction under 4 kg (39.24N) load (Time

389 Sec, Speed 600 rpm, Track dia 80mm)


56/64


57/64

% Kyanitefor

reinforceme

nt

0% 3% 5% 7%

Time in

Hour Corrosion Rate (mpy)

24 0.0148 0.0136 0.0113 0.0093

48 0.0088 0.0086 0.0058 0.0052

72 0.0046 0.0044 0.0041 0.0038

96 0.0045 0.0042 0.0034 0.0029

After immersing in 3.5 % NaClsolution for 96 h, the mass loss of all

samples is so slight that it can be almost ignored. After being immersed in 3.5%

NaCl solutions for 96 h, the mass losses of base matrix and Al2SiO5 addition areshown in Fig.6.26. The mass loss of base matrix in 3.5% NaCl solution is 0.0045

mpy but that of 7% Al2SiO5 addition is only 0.0029 mpy, which indicates the better

corrosion resistance of composites in comparison with base matrix. The immersion

corrosion results confirm the above discussed effects of different percentage of

Kyanite on corrosion resistance and shows obvious differences in corrosion

performance of base matrix and composites.

Corrosion rate values in 3.5 % NaCl for different percentage of Kyanite with

varying exposure time

00.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

24 48 72 96

Corrosionrate,mpy

Exposure time in hour

0

3

5

7


58/64


59/64

Increase of reinforcement percentage posses increase in


60/64

Increase of reinforcement percentage posses increase in

percentage elongation of specimen.

Hardness does not improved satisfactorily and this attribute

is due to the property that kyanite minerals hardness varies indifferent directions.

Al- Al2SiO5 composites provides better resistance for

thermal properties as the kyanite is used for higher thermal

applications such as spark plug, lining in refractories offurnaces etc.

Al- Al2SiO5 composites fabrication is much cheaper

compared to other composites as the cost of kyanite is Rs

10/kg.

The tensile fracture surface was rough and covered with a

healthy population of voids of varying size, dimples of

varying size and shape, and isolated pockets of fine

microscopic cracks.


61/64

A compromise is necessary when deciding how much

kyanite should be added to

enhance the mechanical properties of the composite without

sacrificing too much of its hardness and hence its wearresistance.

Dry sliding wear of Al- Al2SiO5 particulate composite was

found to decrease with kyanite content and touched a

minimum wear rate. The coefficient of friction of Al- Al2SiO5 composite was

also found to decrease with addition of 5wt% kyanite

particles and recorded a 2 times lower value than the base

matrix at 4 kg and 6 kg . In NaOH and NaCl solutions, Al- Al2SiO5 composite

exhibits improved corrosion resistance in comparison with

base matrix.


62/64

Hot worked (i.e., hot pressed) and mechanically processed (i.e., by


63/64

secondary mechanical working like rolling, drawing, extrusion, etc)

materials will definitely yield better results.

Fabrication of aluminiumkyanite MMCs with finer and higherpercentage of reinforcements provide much improved properties.

Alloys of aluminium like 6061. 7075, 8090, 2024, 7001 and 8091 can be

used as the matrix materials with traces of kyanite sillimanite,

alumina, and beryllium for crystal refinement.

Percentage of alumina and silicon-di-oxide in kyanite may be varied and

fabricated to obtain much better results.

Percentage of alumina and silicon-di-oxide other polymorphs of alumina-

silicate like sillimanite, andalusite may be tried.


64/64

Aluminium Kyanite Composite New

Documents

Transcript of Aluminium Kyanite Composite New