Download What is a composite material

Materials Engineering
Lecture 13:
Composite materials
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
Structural classification of
Composites
composites
Particle reinforced
Reinforce Al
Reinforced ceramics
Fiber reinforced
Fiberglass
Glass-polyester
composite
Structural
Composite
ceramics
Matrix and dispersed phase


Matrix: continuous phase surrounding the
other phases
Dispersed phase: inclusion
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
Cermets

Ceramic metals
Ni-YSZ
Co / Ni – WC / TiC
Reinforced Polymers
Concrete

Matrix: cement + dispersed sand, gravel

Reinforced concrete: concrete + iron
Fiber reinforced composited

Whiskers:
very thin
and long
single
crystals

Fibers

Metal wires