Ageing

A change in the properties of certain metals and alloys that occurs at ambient or moderately elevated temperatures after hot working, heat treatment, or a cold working operation.

The ageing of aluminium alloys generally occurs slowly at atmospheric temperatures and more rapidly at higher temperatures.

Aluminum and some metal alloys will become hard and even brittle with age which is an unwanted characteristic. On the other hand when paint or cement harden over time, this process may be a desirable characteristic.

See also: Cold Working, Heat Treatment.