1. Materials Engineering
Lecture 13:
Composite materials

2. What is a composite material
Wood: cellulose (strong and flexible polymer) + lignin (soft amorphous polymer)
Pearlitic steels: soft and ductile a-ferrite + strong, hard and brittle cementite
↑ These are NOT referred to as composites
Composite: multiphase artificial material having distinct interface and chemically different phases

3. Structural classification of composites
Reinforce Al Reinforced ceramics
Fiberglass Glass-polyester Composite
composite ceramics

4. Matrix and dispersed phase
Matrix: continuous phase surrounding the other phases
Dispersed phase: inclusion

5. Mechanical properties of composites
Properties of a composite depend on:
Matrix material
Dispersed phase material
Amount of the dispersed phase
Geometry of the dispersed phase

6. Cermets
Ceramic metals
Ni-YSZ
Co / Ni – WC / TiC

7. Reinforced Polymers

8. Concrete Matrix: cement + dispersed sand, gravel
Reinforced concrete: concrete + iron

9. Fiber reinforced composited
Whiskers: very thin and long single crystals
Fibers
Metal wires