3. Aging treatments

3.1 Principle

From the dissolved and quenched state, the solid solution is in a supersaturated metastable state. Ageing treatment (tempering) thermally activates a precipitation process of certain additive elements in the form of fine precipitates. This treatment is generally carried out at temperatures between 120 and 260°C. In some cases, however, such as with MgAl8Zn1 or MgAl9Zn1, precipitation can take place at room temperature.

Sometimes, an aging treatment can be carried out from the as-cast state. T5 refers to these as stabilization treatments.

The various aging and "stabilization" heat treatments are carried out either on as-cast alloys, or on alloys that have already undergone solution treatment.

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