Understanding the electrochemical, microstructural and morphological changes during hot rolling from a corrosion perspective

Thermo-mechanical processing of rolled aluminium alloys result in the formation of a deformed near-surface region with different filiform corrosion (FFC) behavior than the underlying bulk. This paper tries to correlate the microstructural, morphological and electrochemical changes occurring on the surface of aluminium sheet, during hot rolling, with the FFC behavior. The alloy under investigation is recycled AA5050. The electrochemical changes taking place in the roll-bite has been profiled and the result has been supported by electron microscopic and optical characterization for better understanding. Factors which may or may not be responsible for FFC susceptibility of rolled AA5050 have been discussed and importance of surface finish has been emphasized.