What occurs during improper heat treatment of aluminium alloys?

Improper heat treatment of aluminium alloys can lead to intergranular corrosion, which is a localized type of corrosion that occurs along the grain boundaries of the metal. This phenomenon is often a consequence of improper cooling rates or temperatures during the heat treatment process. When the alloy is not heat treated correctly, it can cause certain precipitates to form along the grain boundaries, making those areas more susceptible to corrosion.

Intergranular corrosion can significantly diminish the overall integrity and mechanical properties of the aluminium component. It can be particularly detrimental in aerospace applications where material failure could have serious safety implications. Therefore, ensuring proper heat treatment is crucial to maintain the corrosion resistance and mechanical performance of aluminium alloys.

In contrast, while improper heat treatment may sometimes lead to variations in tensile strength, ductility, or thermal properties, these outcomes are not as consistently destructive or specific as intergranular corrosion. This makes intergranular corrosion a significant concern in material performance, particularly for components required to operate in challenging environments.