Title: Alloys and Composites
1Alloys 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.
2Which of these are alloys? Put your hand up if
you can name at least one.
Gold, Aluminium, Steel, Iron, Bronze, Mercury,
Brass, Amalgam.
3Steel ? Iron with a small amount of
carbon Bronze ? Copper Tin Brass ? Copper
Zinc Amalgam ? Mercury Silver
4Metals have a crystal structure their atoms
line up in regular patterns.
5But they are rarely perfect.
6Another elements atoms can join the lattice.
7Alloying atoms are of a different size.
8These 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
9Why is an alloy a solid solution?
Because alien atoms are distributed amongst the
atoms in the parent crystal.
10Advantages
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.
11Composites
A Composite material is one made from two
different materials, which have different
properties. Basically it is a polymer (plastic)
with reinforcing fibre inside.
12Carbon Fibre Matting
13A matrix of fibres is held in place by a resin.
14Whats 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.
15Making Alloys
Melt Mix Allow to cool
16Composites are more difficult to make
Fibreglass boat. Lay the matting in a mould.
Apply resin with a brush. Soak the matting. Let
it cure.
17High 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.
18When Production Engineers get their teeth into
something it looks more complicated. But
composites are still simple Two different
materials joined together.
19(No Transcript)
20What would boy racers do without fibreglass?
21You 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.