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Alloys and Composites

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Describe the advantages of alloys over pure metals. ... Gold, Aluminium, Steel, Iron, Bronze, Mercury, Brass, Amalgam. ... Amalgam Mercury Silver ... – PowerPoint PPT presentation

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Title: Alloys and Composites


1
Alloys and Composites
  • State that an alloy is a solid solution
  • Describe the advantages of alloys over pure
    metals.
  • Describe a composite material, explain how it is
    made.
  • State two applications for composites.
  • Describe two examples of composite materials.

2
Which of these are alloys? Put your hand up if
you can name at least one.
Gold, Aluminium, Steel, Iron, Bronze, Mercury,
Brass, Amalgam.
3
Steel ? Iron with a small amount of
carbon Bronze ? Copper Tin Brass ? Copper
Zinc Amalgam ? Mercury Silver
4
Metals have a crystal structure their atoms
line up in regular patterns.
5
But they are rarely perfect.
6
Another elements atoms can join the lattice.
7
Alloying atoms are of a different size.
8
These Alien atoms
  • Are dissolved in the main crystal structure.
  • They change the physical properties
  • They change the stiffness
  • They change the strength.
  • They change the melting point

9
Why is an alloy a solid solution?
Because alien atoms are distributed amongst the
atoms in the parent crystal.
10
Advantages
Alloys can be designed to have particular
properties. They can be stronger. They can be
stiffer. They can have a high melting point. They
can be used in applications where pure metals
would fail.
11
Composites
A Composite material is one made from two
different materials, which have different
properties. Basically it is a polymer (plastic)
with reinforcing fibre inside.
12
Carbon Fibre Matting
13
A matrix of fibres is held in place by a resin.
14
Whats the difference between an alloy and a
composite?
COMPOSITE mixes at a physical level. You can
see the different materials with your eye or a
simple microscope.
ALLOY mixes at an ATOMIC or MOLECULAR level.
Not even an electron microscope would show you
the structure.
15
Making Alloys
Melt Mix Allow to cool
16
Composites are more difficult to make
Fibreglass boat. Lay the matting in a mould.
Apply resin with a brush. Soak the matting. Let
it cure.
17
High Tech Boat builder. Spray the resin into the
mould. The blades at the Wind turbine factory
(Vestas) are made of fibreglass and are made in a
similar way.
18
When Production Engineers get their teeth into
something it looks more complicated. But
composites are still simple Two different
materials joined together.
19
(No Transcript)
20
What would boy racers do without fibreglass?
21
You will now follow instructions in a worksheet
to encourage you to take a few notes. To help
you the slide show will cycle through
continuously. For those who COOPERATE and do the
job, there is a practical demonstration to have a
go at.
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