Definition: A composite material may be defined as multiphase material that exhibits significant proportion of properties of both the materials and it may also have defined as this is judicious combination of two or materials can provide better combination of properties.

Scientists & Engineers are ingeniously tried to design composite materials by combination. A composite material in present context is artificially prepared multiphase in which the chemically dissimilar phases are separated by distinct interface.

Examples: Natural composite material -

1. Wood: In wood matrix phase is made up of strong soft cellulose fibre surrounded by stiffer material called lignin which is dispersed phase.
2. Bone: Matrix phase is soft protein which is called collagen & hard brittle material called apartite which is brittle & is known as dispersed phase. Synthetic composite material:
3. Spherodized steel: Alpha iron is ductile which is used as matrix phase & cementite is brittle which is used as dispersed phase.

Classification of composite material:

1. Particle reinforced composite:

   • i) Large particle strengthened composite
   • ii) Dispersion strengthened composite

2. Fibre reinforced composite:

   • i) Continuous & aligned
   • ii) Discontinuous & aligned
   • iii) Discontinuous & random

3. Structural composite:

   • i) Laminar composite
   • ii) Sandwich composite