Introduction to Composite Materials

Composite materials are made from the combination of two or more different materials on a macroscopic scale to form a material capable of sustaining loads. It should be noted that the products of microscopic mixing of materials, such as alloying, do not belong to the class of composite materials.

Def. any "engineered material composed of two radically different materials in a tightly bonded matrix and having properties significantly different from either constituent"^[1] is called a composite material.

Composite materials can be identified to belong to three different categories:

1. Fibrous composites
2. Laminated composites
3. Particulate composites

These composites are made from a matrix material that holds fibers of a different material. Fibers have higher stiffness and strength than a bulk object made of the same material because internal defects and dislocations are fewer. The material is thus "more perfect" and hence can sustain higher stresses. Some materials are made of whiskers instead of fibers which have even higher properties, however whiskers can cause pneumonic health issues.