Influence of near-surface deformed layers on filiform corrosion of AA3104 aluminium alloy.

The filiform corrosion behaviour of hot-rolled AA3104 aluminium alloy was investigated in the presence of a near-surface deformed layer produced by hot rolling. Through detailed examination of microstructure of the near-surface deformed layer and observation of the propagation behaviour of filiform corrosion, it was found that lateral development of surface-active filiform corrosion in the deformed layer was promoted by magnesium oxide in bands and manganese-containing dispersoids. Further, successive-pitting filiform corrosion was observed along the underlying grain boundaries of the bulk alloy, which develops into crystallographic corrosion of the grain interiors. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]