Composite Materials Through ages, man have become more innovative in discovering new materials, cost reduction techniques aiding life to exist far more better.
What is a composite material? <ul><li>often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or microscopic scale within the finished structure. </li></ul>
<ul><li>two materials in which one of the materials, called the reinforcing phase, is in the form of fibers, sheets, or particles , and is embedded in the other materials called the matrix phase. The reinforcing material and the matrix material can be metal, ceramic, or polymer. Composites are used because overall properties of the composites are superior to those of the individual components. </li></ul>
<ul><li>Wattle and daub is one of the oldest manmade composite materials, at over 6000 years old. Concrete is also a composite material, and is used more than any other man-made material in the world. As of 2006, about 7.5 billion cubic metres of concrete are made each year—more than one cubic metre for every person on Earth. </li></ul>
Particle-reinforced composites <ul><li>* Used in particle reinforcing </li></ul><ul><li>- ceramics, glasses (small mineral particles) </li></ul><ul><li>- metal particles ( aluminium, and amorphous materials ) polymers and carbon black </li></ul>
Why particles are used? <ul><li>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 . </li></ul>
Example: <ul><li>CONCRETE where the aggregtes ( sand and gravel) are the particles and cement is the matrix. Particle reinforced composites support higher tensile, compressive and shear stresses. </li></ul>
Fiber-reinforced composites <ul><li>Fiber-reinforced Composites are made of: </li></ul><ul><li>metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers . </li></ul><ul><li>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 ) </li></ul>
Uses of Fiber-reinforced composites <ul><li>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 </li></ul>Fiber orientation in fiber reinforced composites.
Structural composites <ul><li>The properties of structural composites depend on: </li></ul><ul><li>- Constituents </li></ul><ul><li>- Geometrical design </li></ul>