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Classification of the Composite
Materials
1. Definition
2. Constituents of the Composite Materials
3. Classification of the Composite Materials
1. Definition Composites are materials
made from two or more constituent
materials with different physical and
chemical properties, that when combined,
produce a material with characteristics
different from the individual components.
The
individual
components
remain
separate and distinct within the finished
structure. The new material may be
preferred for many reasons: common
examples include materials which are
stronger, lighter or less expensive when
compared to traditional materials
Constituents
of
the
Composite
Materials
The main constituents of composites are the matrix and the
reinforcement materials. The matrix forms the volume of the
composite material within which the reinforcing agent is imbedded.
The matrix fit together all parts of the composite, while the
reinforcements usually serve to strengthen the composite.
2.
Constituents
of
the
Composite
Materials
2.2. Functions of the matrix
The matrix material can be polymer, metal or other unorganic substance.
The Matrix Material:
Provides the bulk form of the part or product made of the composite
material;
Holds the imbedded phase in place, usually enclosing and often
concealing it;
When a load is applied, the matrix shares the load with the secondary
phase, in some cases deforming so that the stress is essentially born by
the reinforcing agent.
2. Constituents of the Composite
Materials
Materials for FibersFiber materials in
fiber-reinforced composites:
Glass – most widely used filament;
Carbon – high elastic modulus;
Boron – very high elastic modulus;
Polymers – Kevlar;
Ceramics – SiC and Al2O3
Metals – steel.
The most important commercial use of
fibers is in polymer composites.
2. Constituents of the Composite Materials
Particles and Flakes
A second common shape of imbedded
phase are particles , ranging in size from
microscopic to macroscopic.
Flakes
are
basically
two-dimensional
particles - small flat platelets
The
distribution
of
particles
in
the
composite matrix is random, and therefore
strength and other properties of the
composite material are usually isotropic.
Strengthening
particle size
mechanism
depends
on
3.
Classification
of
the
Composite
Materials
After the kind of the matrix composites can be devided into three
groups:
Metal Matrix Composites (MMCs) - mixtures of ceramics and metals, such as
cemented carbides and other cermets;
Ceramic Matrix Composites (CMCs) - Al2O3 and SiC imbedded with fibers to
improve properties, especially in high temperature applications;
Polymer Matrix Composites (PMCs) - thermosetting resins are widely used in
PMCs.
Examples: epoxy and polyester with fiber reinforcement, and phenolic with
powders
Constituents
remain separate and distinct
reinforcement
imbedded
bulk
enclosing
concealing
load
Flakes
Filament
Kevlar
two-dimensional particles - small flat platelets
cermets;
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