Relationship between corrosion rate of 5083 aluminum alloy in alkaline solution and residual stress induced by cold rolling

The corrosion rate of 5083 aluminum alloy cold rolled by a constant reduction rate (10% per pass) or a constant reduction amount (10% of original thickness per pass) method was measured in a 0.5mol/l-NaOH solution at 40°C. The changes in corrosion rate with the total reduction correspond very well to the changes in residual stress of the samples. For the sheets rolled by the constant rate method, the corrosion rate and the residual stress show the maximum at about 50% total reduction. In the case of constant amount rolling, both show two maxima at 30% and 80%, and show a minimum at 50% total reduction. These tendencies can be understood from the fact that the deformation process, which has the characteristic of the development of shearing band in the case of 5083 alloy, differs in the two rolling methods.