6: Alloys

Question 1

What is an alloy?

Answer 1

A mixture of two or more elements, at least one being a metal

Question 2

Examples of alloys and their uses

Answer 2

• Amalgam (contains mercury) is used for tooth fillings
• Brass (contains copper and zinc) is used for musical instruments and coins
• Solder (contains lead and tin) is used for joining electrical wires

Question 3

What is unusual about solder compared to the metals it is made from?

Answer 3

The properties of an alloy are different from the properties of the individual metals it is made from.
Leads melting point is 327 degrees
Tins melting point is 232 degrees
However, Solders melting point is 185 degrees

Question 4

What are ‘Shape-memory alloys’?

Answer 4

‘smart alloys’ which if they bend out of shape, they return to their original shape when they are warmed

Question 5

Nitinol in glasses frames

Answer 5

The composition of the alloy is adjusted during manufacture so that the frame returns to its original shape below room temperature.
So if someone sits on their glasses, when they stand up they return to normal shape.