Composite Materials

Composite Materials

Composite Material Defined
- A materials system composed of two or more physically distinct phases whose combination produces aggregate properties that are different from those of its constituents
- Composites are produced when two materials are joined to give a combination of properties that cannot be attained in the original materials. Composite materials may be selected to give unusual combinations of stiffness, strength, weight, high-temperature performance, corrosion resistance, hardness, or conductivity.
Examples:-
Cemented carbides (WC with Co binder)-
Plastic molding compounds containing fillers -
Rubber mixed with carbon black-
- Wood (a natural composite as distinguished from a synthesized composite)

Components in Composite Material
Nearly all composite materials consist of two phases:
- Primary phase - forms the matrix within which the secondary phase is imbedded
- Secondary phase - imbedded phase sometimes referred to as a reinforcing agent, because it usually serves to strengthen the composite
The reinforcing phase may be in the form of fibers, particles, or various other geometries.

Composites consist of:
1. Combination of two or more materials – Composite = matrix + reinforcemen.
Matrix:
material component that surrounds the fiber.-
Usually a ductile, or tough, material w/ low density-
Strength usually = 1/10 (or less) than that of fiber -
Examples include: thermoplastic or thermoset -
Thermoset most common (epoxy, pheneolic)
- Serves to hold the fiber (filler) in a favorable orientation.