Exfoliation corrosion (Topic 11028)

Exfoliation corrosion proceeds in layers parallel to the surface, the layers will flake because of the pressure from the corrosion products. Alloys that are susceptible to intergranular corrosion may also experience exfoliation corrosion when heavily cold worked. The attack is not usually as serious as intergranular corrosion because it is easier to see. However localised effects can be dramatic, such as in the case of fasteners and rivets which are subjected to cold work during assembly and subsequently exposed to service conditions which can give rise to grain boundary precipitation. The cold worked head of the fastener can become completely detached in extreme cases. Such a mode of failure would not be anticipated in 6000-group alloys.