3. WHAT ARE COMPOSITES?
• Composites are created by combining two or more materials to produce a
new material that retains important properties from the original elements
Reinforcing fibers give composites the attributes of high strength and
stiffness.
Mostly Composites are produced by reinforcing a resin matrix
(thermoplastic/thermoset) with fibers like glass fiber, aramid, carbon fiber
and/or natural fibers.
A common example of a composite is concrete. It consists of a binder as a
cement and a reinforcement as a gravel.
4. Reinforcement
Most composites have two constituents, a matrix and reinforcement.
Reinforcement
Composite
Matrix
The reinforcement is usually much stronger and stiffer than the matrix, and that
gives the composite its good properties.
The matrix hold the reinforcements in an orderly pattern, the matrix also helps to
transfer load among the reinforcements.
Reinforcements basically come in three forms:
Particulate,
Continuous fiber.
Discontinuous fiber,
5. MATRIX
• Matrix Surrounds the individual reinforcing elements protecting against
surface damage. It maintains their relative positions. Prevents the
propagation of brittle cracks between individual reinforcing elements . There
are other types of matrices, such as
• metal or ceramic, but plastics are the most .
e.g.-thermoplastic and thermo setting polymers,
metal, carbon etc.
7. Métal matrix composites (MMC)
MMC are made by dispersing a reinforcing material into a metal matrix. The
reinforcement surface can be coated to prevent a chemical reaction with the
matrix.
-- For example, carbon fibers are commonly used in aluminum matrix to
synthesize composites showing low density and high strength.
However, carbon reacts with aluminum to generate a brittle and water-
soluble compound Al4C3 on the surface of the fiber. To prevent this
reaction, the carbon fibers are coated with nickel or titanium boride.
8. Common matrix in mmc
In structural applications, the matrix is usually a lighter metal
such as aluminum, magnesium, or titanium, and provides a
compliant support for the reinforcement.
In high temperature applications, cobalt and cobalt-nickel
alloy matrices are common
9. Reinforcement to MMC
The reinforcement can be either continuous, or discontinuous..
Discontinuous MMC can be worked with standard metalworking
techniques, such as extrusion, forging or rolling.
In addition, they may be machined using conventional techniques, but
commonly would need the use of polycrystalline diamond tooling (PCD).
10. Manufacturing Methods of MMC
MMC manufacturing can be broken into three types:
solid, liquid, and vapor.
Solid state methods:-
1)-Powder blending and consolidation (powder
metallurgy):-
Powdered metal and discontinuous reinforcement are mixed and then
bonded through a process of compaction, degassing, and thermo-mechanical
treatment (possibly via hot isostatic pressing (HIP) or extrusion).
2)-Foil diffusion bonding:-Layers of metal foil are sandwiched with
long fibers, and then pressed through to form a matrix.
11.
12. Liquid state methods FOR MMC
1)-Electroplating :- A solution containing metal ions loaded
with reinforcing particles is co-deposited forming a composite
material.
2)-Squeeze casting:-
Molten metal is injected into a
form with fibers preplaced inside it.
13. • 3)-Spray deposition:- Molten metal is sprayed onto a
continuous fiber substrate.
• Vapor deposition
Physical vapor deposition: The fiber is passed through a thick
cloud of vaporized metal, coating it.
14. APPLICATION OF
COMPOSITES
Applications of Métal matrix composites (MMC)–
Carbide drills are often made from a
tough cobalt matrix with hard
tungsten carbide particles inside.
15. Tank Armors .
Some tank armors may be made from metal matrix composites, probably steel
reinforced with boron nitride. Boron nitride is a good reinforcement for steel because
it is very stiff and it does not dissolve in molten steel.
.
16.
17. Honda , Toyotas automobiles has
used aluminum metal matrix composite
cylinder liners in some of their engines,
Specialized Bicycles has used aluminum
MMC compounds for its top of the range
bicycle frames for several years. Griffen
Bicycles also makes boron
carbide-aluminum MMC bike frames,
and Univega briefly did so as well.
18. Some automotive disc brakes use MMC. Modern high-performance sport cars, such as
those built by Porsche, use rotors made of carbon fiber within a silicon carbide matrix
because of its high specific heat and thermal conductivity
19. Properties of MMC products
• Tensile strength of composites is four to six times greater than that of
conventional materials like steel, aluminum etc.
• Improved torsion stiffness and impact properties .
• Higher fatigue endurance limit (up to 60% of the ultimate tensile strength)
• 30-45% lighter than aluminum structures designed for the same functional
requirements .
• Composites are less noisy while in operation and provide lower vibration
transmission
• Composites are more versatile and complex design
requirements
20. Ceramic matrix composites
Ceramic matrix composites (CMCs) are a subgroup of composite materials
as well as a subgroup of technical ceramics.
They consist of ceramic fibers embedded in a ceramic matrix, thus forming
a ceramic fiber reinforced ceramic (CFRC) material.
The matrix and fibers can consist of any ceramic material, whereby carbon
and carbon fibers can also be considered a ceramic material.
Generally, CMC names include a combination of type of fiber / type of
matrix. For example, C/C stands for carbon-fiber-reinforced carbon
(carbon/carbon), or C/ SiC for carbon-fiber-reinforced silicon carbide.
• REINFORCEMENT- SiC (Silicon carbide)
• MATRIX-Cu Metal
24. Applications Of ceramic matrix composites
Heat shield systems for space vehicles, which are needed during the re-entry phase,
where high temperatures, thermal shock conditions and heavy vibration loads take place.
Transparent concrete
.
25.
26. • CMC for high-temperature gas turbines such as combustion
chambers, and turbine blades.
• CMC for burners, flame holders, and hot gas ducts, where the
use of oxide CMCs has found its way.
• Disks breaks and brake system components, which experience
extreme thermal shock
28. • Basic advantage of CMC is it withstand high temperature without damaging.
• Long life offers excellent fatigue, impact, environmental resistance and reduced
maintenance.
• Composites enjoy reduced maintenance cost
• Composites exhibit excellent corrosion resistance and fire retardant capability
• Improved appearance with smooth surfaces and readily incorporable integral
decorative melamine are other characteristics of composites
• Composite parts can eliminate joints/fasteners, providing part simplification and
integrated design.
• 25% reduction in weight
• 95% reduction in components by combining parts and forms into simpler molded
parts.
29. Industries in Pakistan
1. EMCO Industries:
19-Km, Lahore Sheikhupura Road, Lahore
Ali Ceramic Industries, Lahore, Pakistan
2-K.M., Sheikhupura Road, P.O. Kot Abdul Malik,, Pakistan
Royalcosmo Group Of Companies(pvt)
Addah Town Daska Road, Sialkot Pakistan
Dynamic Tooling Services
Office No.301, 3rd Floor,
Royal Center, Blue Are, Fazal-EHaque
Road, Islamabad, Pakistan