1. By: Engr. Rizwan Nasir B.Sc. Chemical Engineering 13 October, 2009
Composite Materials
By:
Engr. Rizwan Nasir
B.Sc. Chemical Engineering
13 October, 2009

2. Definition
The word 'composites' has a modern ring.  But using the high strength of fibres to stiffen and strengthen a cheap matrix material is probably older than the wheel. almost all natural materials which must bear load--wood, bone, muscle--are composites.
The composite industry, however, is new.  It has grown rapidly in the past 30 years with the development of fibrous composites..."

3. Composite materials – Introduction
Definition: a material composed of 2 or more constituents
Reinforcement phase (e.g., Fibers)
Binder phase (e.g., compliant matrix)
Advantages
High strength and stiffness (rigidity)
Low weight ratio
Material can be designed in addition to the structure
Can manufacture structures and eliminate joints

4. Natural composites
Fish fins
Muscles
Bird wings
Wood

5. Composite materials are like sandwiches
Composite materials are like sandwiches.  A good sandwich contains a variety of ingredients to yield a taste that no single ingredient could provide by itself. 
Similarly, composite materials are those which are formed from two or more materials producing properties or characteristics that could not be obtained from any one material. 
Composites consist of one or more discontinuous phases fixed in a continuous phase. The discontinuous phase is usually harder and stronger than the continuous phase and is called the reinforcement or reinforcing material, whereas the continuous phase is termed the matrix.

7. Applications
Aerospace industry
Sporting goods
Automotive
Construction

8. Types of Composites MMC’s CMC’s PMC’s Elemental (Carbon, Boron, etc.)
Matrix phase/Reinforcement Phase
Metal
Ceramic
Polymer
Powder metallurgy parts – combining immiscible metals
Cermets (ceramic-metal composite)
Brake pads
Cermets, TiC, TiCN
Cemented carbides – used in tools
Fiber-reinforced metals
SiC reinforced Al2O3
Tool materials
Fiberglass
Kevlar fibers in an epoxy matrix
Elemental (Carbon, Boron, etc.)
Fiber reinforced metals
Auto parts
aerospace
Rubber with carbon (tires)
Boron, Carbon reinforced plastics
MMC’s CMC’s PMC’s
Metal Matrix Composites Ceramic Matrix Comp’s Polymer Matrix Comp’s

10. Fibers - Glass Most widely used fiber
Uses: piping, tanks, boats, sporting goods
Advantages
low cost
Corrosion resistance
Low cost relative to other composites:
Disadvantages
Relatively low strength
High elongation
Moderate strength and weight
Types:
E-Glass - electrical, cheaper
S-Glass - high strength

11. Fibers - Aramid (Kevlar, Twaron)
Uses:
High performance replacement for glass fiber
Examples
shield, protective clothing, industrial, sporting goods
Advantages:
Higher strength and lighter than glass
More ductile than carbon

12. Fibers - Carbon 2nd most widely used fiber Examples Advantages
aerospace, sporting goods
Advantages
high stiffness and strength
Low density
Intermediate cost
Properties:
Diameter: 5-8 microns, smaller than human hair
Fibers grouped into tows or yarns of 2-12k fibers

13. PAN (Polyacrylonitrile)
Carbon fiber composite material are produced by PAN with the help of these processing stages:
Stabilization
Carbonization
Graphitization

14. Stabilization
In this process PAN fiber are stretched to align the fiber network with each network.
Then they are oxidize in air at temperature about 200 – 220oC while holding in tension.

15. Carbonization
In this process the high strength carbon fiber is carbonized.
The stabilized PAN fiber are heated until they become transformed into carbon fibers by the elimination of oxygen, nitrogen and hydrogen.
The carbonization process is carried out at the temperature of 1000 – 1500oC

16. Graphitization
It is used if we desired the product of high elasticity.
This process is carried out at the temperature of 1800oC.

17. Aramids Fiber Aramid fiber is the name for aromatic poly amide fibers.
Aramid fibers are available under the name of Kevlar.
At the present time there are two commercial types are available.
Kevlar – 29
Kevlar – 49

18. Kvelar – 29
It is the low density high strength aramid fiber such application as cables, ropes and missiles.

19. Kevlar – 49
It is a useful fibre as reinforcement plastic in composite material for aerospace, automobile, industrial application and also shipping industry .
Its density is higher than Kevlar – 29.
In general Kevlar aramid is used for high performance composite application where light weight, high strength, resistance to stress.

20. An education isn't how much you have committed to memory, or even how much you know. It's being able to differentiate between what you do know and what you don't.
Anatole France

21. Thank You!