Corrosion behaviour of friction stir welded AA7108 T79 aluminium alloy

The corrosion behaviour of a friction stir welded AA7108 T79 aluminium alloy has been investigated using accelerated testing (ASTM G34 EXCO) and electrochemical measurements. The welded alloy showed the expected zones associated with friction stir welding, namely nugget, thermomechanically affected zone and heat affected zone. Corrosion testing revealed that the edge regions of the thermomechanically affected zone were most susceptible to corrosion. The localized corrosion occurs intergranularly due to the non-uniform distribution of η/η′ (MgZn2) precipitates within the thermomechanically affected zone.