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Adding other metals to aluminium
An alloy of aluminium contains small amounts of other metals.
Explain why other metals are added to aluminium.
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Marking points
- 1 State that the added metal atoms are different sizes from aluminium atoms.
- 2 State that the different-sized atoms distort the layers of aluminium atoms.
- 3 State that the layers cannot slide, or cannot slide over each other easily.
- 4 Link the reduced sliding to the alloy being harder or stronger.
Full-mark answer
The other metal atoms are different sizes from aluminium atoms. This distorts the layers of aluminium atoms, so the layers cannot slide over each other easily. This makes the alloy harder or stronger.