Page 27 - Curriculum Visions Dynamic Book

More expensive but more lightweight are aluminium-copper-lithium alloys. Their main use is for aircraft manufacture because reducing weight is of prime concern.
The highest strength alloys are aluminium- zinc-magnesium. Some also contain copper. They can be treated to reduce the likelihood of metal fatigue. Aluminium-silicon alloys are used for welding wire because the silicon makes the molten aluminium more runny.
Another example is when the surface needs to be protected from corrosion. Anodizing is a treatment applied to aluminium to make it harder and more corrosion resistant (see page 32).
(Below) Stainless steel
is an alloy. It is used
to superb effect in the Gateway Arch, St. Louis.
(Left) “Steel” hawsers used, for example, on suspension bridges; they are usually an alloy. If they were not, they would rust.
(Below) Virtually every piece of metal on this fighter plane is an alloy; in particular, most of the fuselage is made of aluminium alloys. By making alloys, metals can be given exactly the right qualities for their purpose.
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