a materials properties
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Materials, their Properties & Uses
Introduction to Materials
Properties of Materials
Metals Plastics
Woods
Composites
Heat Treatment
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Introduction to Materials
Materials are used to make or build objects.
During the past 200 years there has been an
enormous increase in the range of materials
available to us. It is therefore important that thecorrect materials be used for a particular use.
In Selecting the best material you need to look
at 4 things: Physical properties, Cost and Time,Shaping and Forming and Availability.
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Selecting the best materialA checklist
2 WHAT COST?
The materials
The extras (fittings etc)
3 SHAPING & FORMING
Cutting out
Moulding
Casting
Joining
4 AVAILABILITY
Are they easy to obtain
including fittings.
1 PHYSICAL PROPERTIES
Hardness
Tensile Strength
Compressive Strength
Shear StrengthStiffness
Toughness
Malleable
Corrosive
Appearance
Weight
Conductivity
S
E
L
EC
T
IO
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Properties of Materials
Each material has many properties. It is
incorrect, for example to describe a material
as just strong or weak as for example
concrete is strong in compression but weak
in tension.
Hardness Toughness Strength
Brittleness Malleability DuctilityElasticity Plasticity Conductivity
Density Fatigue Stiffness
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Hardness
The ability of a material to resist wear
indentation and scratching.
An example of a
hardness test that
can be carriedout in the lab.
Different materials
are used and the
depth of indentationmeasured
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Toughness
The ability of a material to withstand
blows or sudden impact.
Different materials are
used, the hammer is
swung from the same
height each time about
a fixed fulcrum. The
distance travelled
after impact or
fracture is used to find
toughness
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Strength
The ability of a material to withstand
forces of tension, compression and torsion
Tensile Strengththe ability to withstand
pulling forces or Tension forces
Compressive Strengththe ability to withstand
squeezing forces orCompression forces
Torsional Strengththe ability to withstandtwisting forces orTorsion forces
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Brittleness
The same as the
toughness test
however thosematerials that
fracture easily
are said to be
brittle.
A material that is easily fractured by
impact is said to be brittle e.g. Glass
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Malleability
A material that can be rolled or hammered
into shape without rupture.
As ring risesthe side of
Coke can is
thinned out
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Ductility
A material that can be pulled or stretched
into a thin wire or thread.
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Elasticity
The ability of a material to return to its
original shape after deformation.
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Plasticity
The ability of a material to be permanently
deformed without fracture..
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Conductivity
The ability of a material to allow Heat or
electricity to flow through it.
Ball Bearingdrops from most
conductive 1st.
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Density
Is the mass of 1 cubic centimetre (cm3) of a
substance. (Mass per unit Volume)
Q. Which is heavier a tonne of feathers or
a tonne of lead?
Q. Which has the greatest density?
Density =Mass
Volume
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Fatigue
Occurs when materials have become
overworked and fracture or fail.
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Stiffness
The ability of a material to resist bending
deformation.
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