composite is a combination of two or more chemically distinct material that result unique and better mechanical , thermal,electrical and magnetism properties

1. Reinforcement technique in composites

2. Natural composites

3. Introduction
• A composite material can be
defined as an unique or better
combination of two or more
chemically distinct materials
that results in improve the
properties over the individual
components
• It consist of one or more
discontinous phase or
reinforcing phase in form of
fibers,particles,whiskers or
lamellae that embedded in a
continuous phase or matrix
phase in form of
polymer,metal or ceramic

5. So why use composites
 It provides high strength and stiffness to weight ratio
 High creep resistance
 Weight reduction
 Stand up well to corrosion and oxidation
 Possible to make unique properties according to
requirements
 Can be moulded into any shape
 Durable and higher flexibity
 High tensile strength at elevated temperature
 Fatigue resistance and higher toughness

6. Matrix phase
• It is the primary or continuous phase and surrounds
the reinforcements
• Usually matrix are ductile or tough material
Functions
 Binds or holds the reinforcements together and
mechanically supporting the reinforcements
 Matrix shares or transfers the applied load with the
secondary phase for strengthening the composite
 Protect the reinforcement from surface damage
 Build up the bulk form of composite
 Prevents the propagation of brittle cracks

7. Matrix phase(con’t)
Matrix
Metal matrix
composites
Ceramic
matrix
composites
Polymer
matrix
composites

8. MMC
• It contains particulates,whiskers , ceramics or
fibers act as reinforcement phase that dispersed in
a metal matrix.
• Advantages
• High strength and stiff due to strong reinforcement
and matrix bonding
• Higher operating temperature
• Non-flammability
• Greater resistance to degradation by organic acid
• Enhancement of modulus
• Production and Application

9. MMC(con’t)

10. PMC
• It consisting of a polymer resin as a matrix that
combined with a fibrous reinforcing phase
• Matrix is relatively soft and flexible
• Cheaper and easy to fabrication
• Reinforcement mainly bear the load
• Thermosetting PMC
• Thermoplastic PMC
• Limitation
• Low maximum working temperature
• Sensitive to radiation,moisture and chemicals

11. PMC (Con’t)
PMC
GFRP CFRP AFRP

12. CMC
• Continuous phase is ceramics in form of
oxides,carbides,nitrides,borides ,glasses or silicates and
the reinforcements used are Sic, BN,ZrO2 or C in form
of fibres,whiskers or particulates .
• Corrosion and oxidation resistance
• Can be use in higher temperature than metal and
polymers
• Processing
• Example and Application

13. Reinforcements
• A reinforcements is the strong
and stiff integral component
which is incorporated into the
matrix to achieve desired
properties
• They have low ductility
• It is the dispersed phase which
normally bears the majority of
stress
• Having low density
• Strengthening mechanism
depends strongly on the
geometry of the reinforcement

14. Reinforcement(con’t)

15. Particle reinforced composites
• Particles are used to
increase the modulus
of the matrix, decrease
the permeability and
ductility of matrix
• Provide high
tensile,compressive and
shear stress
• These harder and stiffer
components may be of
macro,micro or
nanoscopic scale size

16. Particle reinforcement(con’t)
• Large particle
Interaction between
particles and matrix
are not on the atomic
or molecular level
Example- concrete
The volume fraction of
the two phase
influences the
mechanical behavior

17. Particle reinforced
composite(con’t)
Dispersion strengthened
composites-
Strengthening of materials by
dispersion of very small hard
particles (0.1 to 100 nm) uniformly
within load-bearing matrix
Plastic deformation is restricted
Tensile strength and hardness
improved
Strengthening is retained at
elevated temperature

18. Fiber reinforced composites
• The dispersed
phase in fiber form
• High strength to
weight and
modulus to weight
ratio
• Low specific
gravity and high
fatigue
resistance

19. Fiber reinforced composite(con’t)
• Continuous fibers- When fiber lengths greater
than the critical length
• Highly effective in strengthening the material
• Discontinuous fibers- When fiber lengths
shorter than the critical length
• Having modulus and tensile strength 50-70% of their
continuous counterparts
• Cheaper and easy to fabricate into complicated
shapes
• Random fibers- These ate discrete or chopped
fibers
• Isotropic and cheaper
• Aligned fibers- provide higher strength

20. Fiber reinforcement
phase(con’t)
Fibers
phase
Whisker
fiberWire

21. Structural composites
• A structural composites is
normally composed of both
homogeneous or composite
materials,the properties of
which depend not only on the
properties of the but also on
the geometrical design of the
structural composites
• Laminar composite
• Sandwich panel
 Faces
 core

22. Structural composites(con’t)

23. Nanocomposites
• These are composites in
which at least one of the
phases is present on a
nanometric scale .
• Nanosized metal or
semiconductor particle act as
reinforcement phase that
embedded in different matrix
phase like metal,polymer or
ceramic
• It improve the
electrical,magnetic,mechan
ical and optical properties
• Higher surface to volume
ratio
Nanocomposites
Nanoparti
cles
Polymer

24. Limitations
• Repair can be difficult
• Operating temperature can be an issue for
polymeric matrix
• Fabrication difficulties
• Expensive
• Manufacturing method for shaping
composite material is time consuming
• Physical properties of most of composites
are anisotropic

29. Conclusion