Fiber Strengthening

Fiber Strengthening

Fiber Strengthening
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In fiber strengthening, materials are
strengthened by adding fine fibers into a
ductile matrix .
Fiber strengthened materials are called as
composite material.
Example : Glass-fiber-reinforced polymer.
Fiber – Fine filaments, wires or whiskers which
have diameters ranging from 1μm to 250 μm .
This may be continuous or discontinuous one.
Matrix material – Material that glues the fibers
together and also transfer the stress to them.

Fiber Strengthening
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Properties of Fiber
• High strength
• High elastic modulus

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Properties of matrix material
• Ductile
• Non reactive with the fiber.

Fiber Strengthening

Fiber Strengthening
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Different fiber materials are
• Metallic fiber
 Tungsten
 Stainless steel
• Non-metallic fiber (Ceramics)
 Al2O3
 Boron
 Boron nitride
 Graphite
 Glass
 Silicon carbide
• Non –metallic fiber (polymer)
 Kevlar

Fiber Strengthening
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Different matrix materials are
• Metals
• Polymers
• Ceramics

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In fiber strengthening, the behaviour
of fiber is elastic in nature. Hence
dislocation theory not incorporated
here.

Fiber Strengthening
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Function of fiber
• carry all of the tensile load.

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Function of the matrix material
• Transmit the load to the fibers
• Protect the fibers from surface damage
• Separate the individual fibers
• Blunt the crack which arises from fiber

damage.

Fiber strengthening
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When the fiber strengthened material
is subjected to the external load, the
following stresses will develop in the
fiber.
1. At the fiber matrix interface shear stress

develops.
2. At the fiber tensile stress develops

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Superplastic behaviour occurs at
temperature greater than half the
absolute melting temp.
Examples are tin – lead Alloy, Zinc –
Al alloy, Titanium alloy.
Used in sheet metal forming
operation.
Application : Missile parts.

SUPERPLASTICITY OF NANOCRYSTALLINE COPPER
AT ROOM TEMPERATURE