Metal matrix composites and Metal matrix Ceramics

 Muhammad Sajjad BSME-01113138
 Muhammad Umer BSME-01113128
 Hafiz Sarmad BSME-01113100
Section:C
Mechanical Engineering
The University Of Lahore

 Two inherently different materials that when
combined together produce a material with
properties that exceed the constituent
materials.
OR
 A combination of two or more simple materials
to yield another material with better properties.

 One of the first fiber-reinforced polymer
composites made by humans was a
raincoat, created in the middle of the
nineteenth century, by a Scottish fellow
by the name of Charles Macintosh, who
came up with a clever idea.

He took two layers of cotton
fabric and embedded them
in natural rubber, making a
three-layered sandwich.
Remember, cotton is a form
of a natural polymer called
cellulose. This made for
good raincoats
because, while the rubber
made it waterproof, the
cotton layers made it
comfortable to wear.

Metal Matrix Composites
Composites are
combinations of two
materials in which one of
the material is called the
reinforcing phase, is in
the form of
fibers, sheets, or
particles, and is
embedded in the other
material called the matrix
phase.
Composite = matrix +

 Typically, reinforcing materials are strong
with low densities while the matrix is
usually a ductile or tough material. If the
composite is designed and fabricated
correctly, it combines the strength of the
reinforcement with the toughness of the
matrix to achieve a combination of desirable
properties not available in any single
conventional material.

Metal Matrix composites
Composites are usually
made of two parts, a fiber
and a matrix. The fiber
can be glass, carbon
fiber, or polyethylene.
The matrix, which is the
stuff that holds the
fibers, is usually a
thermoset like an epoxy
resin.

 The fiber is embedded in the matrix in order to
make the matrix stronger. Fiber-reinforced
composites have two things going for them.
They are strong and light. They are often
stronger than steel, but weigh much less. This
means that composites can be used to make
automobiles lighter.
 Composites can also be used to imitate natural
materials, like in musical instruments where
use of wood is common.

Aligned Fibers
The properties of aligned
fiber-reinforced
composite materials are
highly anisotropic. The
longitudinal tensile
strength will be high
whereas the transverse
tensile strength can be
much less than even the
matrix tensile strength.

Random Fibers
This is also called
discrete fibers. The
strength will not be
as high as with
aligned
fibers, however, the
advantage is that the
material will
be istropic and
cheaper.

Woven Fibers
The fibers are
woven into a
fabric which is
layered with the
matrix material to
make a laminated
structure.

Superior mechanical properties in comparison
to short fiber composites (higher modulus,
higher impact properties, higher tensile
strength); elastic properties ~70-90% that of
continuous fiber composites.

 Polyster
 Vinyl Esters
 Epoxy

Polyester
Polyesters have good
mechanical
properties, electrical
properties and chemical
resistance. Polyesters
are amenable to multiple
fabrication techniques
and are low cost.

Vinyl Esters
Vinyl Esters are similar to
polyester in performance.
Vinyl esters have increased
resistance to corrosive
environments as well as a
high degree of moisture
resistance.

Epoxy
Epoxies have improved
strength and stiffness
properties over polyesters.
Epoxies offer excellent
corrosion resistance and
resistance to solvents and
alkalis. Cure cycles are
usually longer than
polyesters, however no by-
products are produced.

• The advantages of
composite materials
are that they are
strong, don’t rust
easily and they are
not heavy in any
way.

• The disadvantages
of composite
materials are that
they are very
expensive to buy
and difficult to stick
to other materials.

• The people who
work with composite
materials are :-
*Footballers
*Ice skaters
*Basket ball players
*Pilots
*Builders etc.

 Liquid state fabrication of Metal Matrix
Composites involves incorporation of
dispersed phase into a molten matrix metal,
followed by its Solidification.
 In order to provide high level of mechanical
properties of the composite, good interfacial
bonding (wetting) between the dispersed phase
and the liquid matrix should be obtained.

 Stir Casting
 Infiltration
 Gas Pressure Infiltration
 Squeeze Casting Infiltration
 Pressure Die Infiltration

 Stir Casting is a liquid state method of
composite materials fabrication, in which a
dispersed phase (particles, short fibers) is
mixed with a molten matrix metal by means of
mechanical stirring.
 Stir Casting is the simplest and the most cost
effective method of liquid state fabrication.
 The liquid composite material is then cast by
conventional casting methods and may also be
processed by conventional Metal forming
technologies.

Stir Casting is characterized
by the following features:
Content of dispersed phase is
limited (usually not more
than 30 vol.%).
Distribution of dispersed
phase throughout the matrix
not perfectly homogeneous.
The technology is relatively
simple and low cost.

Infiltration
Infiltration is a liquid
state method of
composite materials
fabrication, in which a
preformed dispersed
phase
(particles, fibers, woven)
is soaked in a molten
matrix metal, which fills
the space between the
dispersed phase
inclusions.

 Gas Pressure Infiltration is a forced infiltration
method of liquid phase fabrication of Metal
Matrix Composites, using a pressurized gas for
applying pressure on the molten metal and
forcing it to penetrate into a preformed
dispersed phase.

 Gas Pressure Infiltration method is used for
manufacturing large composite parts.
 The method allows using non-coated fibers due
to short contact time of the fibers with the hot
metal.
 In contrast to the methods using mechanical
force, Gas Pressure Infiltration results in low
damage of the fibers.

 Squeeze Casting Infiltration is a forced
infiltration method of liquid phase fabrication
of Metal Matrix Composites, using a movable
mold part (ram) for applying pressure on the
molten metal and forcing it to penetrate into a
performed dispersed phase, placed into the
lower fixed mold part.
 Squeeze Casting Infiltration method is similar
to the Squeeze casting technique used for metal
alloys casting.

 A preform of dispersed phase (particles, fibers) is
placed into the lower fixed mold half.
 A molten metal in a predetermined amount is
poured into the lower mold half.
 The upper movable mold half (ram) moves
downwards and forces the liquid metal to infiltrate
the preform.
 The infiltrated material solidifies under the
pressure.
 The part is removed from the mold by means of
the ejector pin.

 The method is used for manufacturing simple
small parts (automotive engine pistons from
aluminum alloy reinforced by alumina short
fibers).

 Pressure Die Infiltration is a forced infiltration
method of liquid phase fabrication of Metal
Matrix Composites, using a Die casting
technology, when a preformed dispersed phase
(particles, fibers) is placed into a die (mold)
which is then filled with a molten metal
entering the die through a sprue and
penetrating into the preform under the
pressure of a movable piston (plunger).

 Particle-reinforced composites
 Fiber-reinforced composites
 Structural composites

* Used in particle reinforcing
- ceramics, glasses (small mineral particles)
- metal particles (aluminium, and amorphous
materials ) polymers and carbon black

 Particles are used to increase the modulus of
the matrix, to decrease the permeability of the
matrix, to decrease the ductility of the matrix
and also used to produce inexpensive
composites.

 Tennis rackets are most often made out of aluminum
and composite materials. Aluminum rackets are
made of one of several alloys, including a 2 percent
silicon alloy with traces of magnesium, copper and
chromium, and a 10 percent zinc alloy, with
magnesium, copper and chromium.
 Composite rackets contain a range of materials,
including graphite, fiberglass, boron or Kevlar. The
strings are made of nylon, twisted sheep, cow gut or
synthetic gut, but nylon is the most commonly used.

 Fiber-reinforced Composites are made of:
- metals, ceramics, glasses, or polymers that have
been turned into graphite and known as carbon
fibers.
- Fibers increase the modulus of the matrix
material. (strong covalent bonds along the fiber's length
gives them a very high modulus in this direction because
to break or extend the fiber the bonds must also be broken
or moved )

 sports equipment, such as a time-trial racing bicycle frame
which consists of carbon fibers in a thermoset polymer matrix.
Body parts of race cars and some automobiles are composites
made of glass fibers (or fiberglass) in a thermoset matrix
Fiber orientation in fiber
reinforced composites.

 The properties of
structural composites
depend on:
- Constituents
- Geometrical design

 Fiber Craft Industries in Lahore Pakistan
Fiberglass reinforced Plastic pipes usually
known as FRP or GRP pipe.
 Textile Industries:
Hussain Industries in Multan
Nishat Textile Mills in Faislabad and karachi
Chenab Group In Faislabad

 Kowil Group of Industries Sialkot:
Manufacturing Coat of Arms, Flags &
Banners,, Ribbons, Buckles, Metal
Badges, Buttons for Army, Navy, Air
Force, Police, Fire
Department, Colleges, Schools etc.

 S. K. Munir & Co. Lahore
 Manufacturing Uniform Items ( like Boots
, Jackets, Belts etc.) Bullet proof Items (like
Bullet proof Jackets, Helmets etc.)
 Wireless & Communication Equipment (like
walkie talkie, mobile radios , receivers etc.)
 Rescue & Safety Equipment (like fire fighting
equipment, fire proof suits etc.

 In general, the major advantages of Matrix
Composites compared to unreinforced
materials, such as steel and other common
metals, are as follows:

METAL MATRIX COMPOSITES STEEL
 Increased specific
strength and elevated
temperature strength.
 High Corrosion
Resistance
 Much Costly.
 Strength reduces at
high temperatures
due to fire.
 It can corrode.
 Not much Costly.

 Carbon fiber is defined as a fiber containing at
least 92 wt % carbon, while the fiber containing at
least 99 wt % carbon is usually called a graphite
fiber.
 It is a material consisting of several fibers and
composed mostly of carbon atoms.
 Each fiber is about 5 – 10 μm thick in diameter.

The manufacturing of carbon fibers carries
a number of challenges, including:
 The need for more cost effective recovery and
repair.
 Close control required to ensure consistent
quality.
 Health and safety issues
 Skin irritation
 Breathing irritation.

 Carbon fiber is currently produced in relatively limited
quantities mostly via two manufacturing processes:
 Based on pitch (coal tar and petroleum products)
 Based on Polyacrylonitrile (PAN)
o Current global capacity for pitch-based carbon fiber is
estimated at about 3,500 metric tons per year.
 Global use for PAN-based carbon fiber is increasing
rapidly, and total production capacity currently does not
meet the demand.
 PAN-based carbon fiber is more expensive to
produce, hence, limiting its use to high end
applications, (used primarily by aerospace and sporting
equipment industries).

 In the manufacturing process, the raw
material, which is called precursor, is drawn into
long strands or fibers. The fibers are woven into
fabric or combined with other materials that are
molded into desired shapes and sizes.
 There are typically five segments in the
manufacturing of carbon fibers from the PAN
process. These are:
1)Spinning:
 PAN mixed with other ingredients and spun into
fibers, which are washed and stretched.

Stabilizing:
Chemical alteration to stabilize bonding.
Carbonizing:
Stabilized fibers heated to very high
temperature forming tightly bonded carbon
crystals.
Treating the Surface:
Surface of fibers oxidized to improve bonding
properties.

Sizing:
Fibers are coated and wound onto
bobbins, which are loaded onto spinning
machines that twist the fibers into different
size yarns. Instead of being woven into
fabrics, fibers may be formed into composites.
To form composite
materials, heat, pressure, or a vacuum binds
fibers together with a plastic polymer.

 Portable power.
 Rechargeable batteries and fuel cell
electrodes.
 Fiber reinforced plastics, FRP.
 Energy production; windmill blades.
 Building and construction materials.

MUSICAL INSTRUMENTS MOBILE CASE

 The future efforts on carbon fiber research will
be focused on cost reduction and property
improvement.
 The mechanical property of carbon fiber heavily
relies on its microstructure.
 The improvement on the tensile, flexural, and
shear strength of pitch carbon fibers has been
observed by randomizing the graphite
distribution in the fiber transverse direction.

• Ceramics materials are inorganic and nonmetallic
materials. most ceramics are compounds between
metallic and nonmetallic elements for which the
interatomic bonds are either totally ionic or
predominantly ionic but having same covalent
character

 Whitewares
 Refractories
 Glasses
 Abrasives
 Cements

 Crockery
 Floor and wall tiles
 Sanitary-ware
 Electrical porcelain
 Decorative ceramics

 Slurry is a dispersion of ceramic particles in a
liquid carrier, which may also contain additives
such as binders and wetting agents.
Slurry Infiltration method of fabrication of
Ceramic Matrix Composites utilizes a slurry
percolating into a porous reinforcing preform. The
infiltration process is driven by the capillary
forces.
After the infiltration process has completed, the
preform is dried and hot pressed forming a
ceramic matrix composite.

 Slurry infiltration
The reinforcing fibers passe through a
slurry, which penetrates into the porous
structure of the reinforcing phase. The driving
force of the infiltration is capillary effect but the
process may be enhanced by vacuum or
pressure.

 Lay-up
The fibers are wound onto a mandrel. Then it
is dried, cut and laid-up. After drying they are
cut and laid-up on a tooling (mold).
 Hot pressing
Hot pressing is performed at high temperature
and increased pressure, which enhance the
diffusion of the ceramic material between the
particles incorporated into the fibers structure.
The particles consolidate resulting in a low
porosity densified composite.

 Low porosity.
 Good mechanical properties.

 The reinforcing fibers may be damaged by the
high pressure applied in the hot pressing stage.
 Hot pressing operation requires relatively
expensive equipment.
 Relatively small and simple parts may be
fabricated.

Made from natural clays and mixtures
of clays and added crystalline
ceramics.
These include:
 Whitewares
 Structural Clay Products
 Refractory Ceramics

Firebricks for furnaces and ovens.
Have high Silicon or Aluminium
oxide content.
Brick products are used in the
manufacturing plant for iron and
steel, non-ferrous
metals, glass, cements, ceramics, energ
y conversion, petroleum, and
chemical industries.

 Used to provide thermal protection of other
materials in very high temperature
applications, such as steel making
(Tm=1500 C), metal foundry operations, etc.
 They are usually composed of alumina
(Tm=2050 C) and silica along with other
oxides: MgO
(Tm=2850 C), Fe2O3, TiO2, etc., and have
intrinsic porosity typically greater than 10%
by volume.
 Specialized refractories, (those already
mentioned) and BeO, ZrO2, mullite, SiC, and
graphite with low porosity are also used.

 Main ingredient is Silica (SiO2)
 If cooled very slowly will form crystalline
structure.
 If cooled more quickly will form amorphous
structure consisting of disordered and linked
chains of Silicon and Oxygen atoms.
 This accounts for its transparency as it is the
crystal boundaries that scatter the light, causing
reflection.
 Glass can be tempered to increase its toughness
and resistance to cracking.

Three common types of glass:
 Soda-lime glass - 95% of all glass,
windows containers etc.
 Lead glass - contains lead oxide to
improve refractive index
 Borosilicate - contains Boron oxide,
known as Pyrex.

 Flat glass (windows)
 Container glass (bottles)
 Pressed and blown glass (dinnerware)
 Glass fibres (home insulation)
 Advanced/specialty glass (optical
fibres)

The strength of glass
can be enhanced by
inducing compressive
residual stresses at the
surface.
The surface stays in
compression - closing
small scratches and
cracks.
Small Scratches

Good electrical insulators and refractories.
• Magnesium Oxide is used as insulation
material in heating elements and cables.
• Aluminium Oxide
• Beryllium Oxides
• Boron Carbide
• Tungsten Carbide.
• Used as abrasives and cutting tool tips.

 Natural (garnet, diamond, etc.)
 Synthetic abrasives (silicon
carbide, diamond, fused alumina, etc.)
are used for
grinding, cutting, polishing, lapping,
or pressure blasting of materials

 Used to produce concrete
roads, bridges, buildings, dams.

 Advanced ceramic materials have been
developed over the past half century
Applied as thermal barrier coatings to protect
metal structures, wearing surfaces, or as integral
components by themselves.
 Engine applications are very common for this
class of material which includes silicon nitride
(Si3N4), silicon carbide (SiC), Zirconia (ZrO2) and
Alumina (Al2O3)
 Heat resistance and other desirable properties
have lead to the development of methods to
toughen the material by reinforcement with fibers
and whiskers opening up more applications for
ceramics

• Structural: Wear parts, bioceramics, cutting
tools, engine components, armour.
• Electrical: Capacitors, insulators, integrated
circuit packages, piezoelectrics, magnets and
superconductors
• Coatings: Engine components, cutting tools, and
industrial wear parts
• Chemical and environmental:
Filters, membranes, catalysts, and catalyst
supports

Rotor (Alumina)
Gears (Alumina)

Automotive
Components in
Silicon Carbide
Chosen for its heat
and wear
resistance

 Ceramic armour systems are used to protect
military personnel and equipment.
 Advantage: low density of the material can
lead to weight-efficient armour systems.
Typical ceramic materials used in armour
systems include alumina, boron carbide, silicon
carbide, and titanium diboride.
 The ceramic material is discontinuous and is
sandwiched between a more ductile outer and
inner skin.

 Ceramic armour systems are used to protect
military personnel and equipment.
 Advantage: low density of the material can lead
to weight-efficient armour systems.
 Typical ceramic materials used in armour
systems include alumina, boron carbide, silicon
carbide, and titanium diboride.
 The ceramic material is discontinuous and is
sandwiched between a more ductile outer and
inner skin.

• Most of the impact energy is absorbed by the
fracturing of the ceramic and any remaining
kinetic energy is absorbed by the inner
skin, that also serves to contain the fragments
of the ceramic and the projectile preventing
severe impact with the personnel/equipment
being protected.
• This lightweight solution provided an efficient
and removable/replaceable armour system.
Similar systems used on Armoured Personnel
Carrier’s.

Metal matrix composites and Metal matrix Ceramics

Metal matrix composites and Metal matrix Ceramics

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