Aluminium alloy heat treatment classification and basic principle

Aluminium alloy heat treatment classification and basic principle

The function of heat treatment of aluminum and aluminum alloy is to heat the aluminum and aluminum alloy material to a certain temperature and hold it for a certain time to obtain the expected product organization and performance.

Ageing: After solution quenching, the material is kept at room temperature or at a higher temperature for a period of time, the unstable supersaturated solid solution will decompose and the second phase particles will precipitate (or precipitate) from the supersaturated solid solution and be distributed around the alpha (AL) aluminium grain, thus producing a strengthening effect called precipitation (precipitation) strengthening.

1. Natural ageing: Some alloys (such as 2024, etc.) can produce precipitation strengthening at room temperature, called natural ageing.

2. Artificial ageing: some alloys (such as 7075, etc.) at room temperature precipitation strengthening is not obvious, while the precipitation strengthening effect at higher temperatures is obvious, called artificial ageing.

Artificial ageing can be divided into under-ageing and over-ageing.

①Under-aging: In order to obtain certain properties, a lower aging temperature is controlled and a shorter aging time is maintained.

②Over-aging: In order to obtain certain special properties and better overall performance, the aging is carried out at a higher temperature or under a longer holding time.

③Multi-stage ageing: In order to obtain certain special properties and good overall performance, the ageing process is divided into several stages. It can be divided into two stages and three stages of aging

Return treatment: in order to improve plasticity, cold forming or correction of shape tolerances, will have been quenched and aged products, at high temperatures for a shorter period of time can be restored to the new quenching state called return treatment.