An investigation of serrated yielding in 5000 series aluminum alloys

The effect of different thermal treatment temperatures (from 472 to 783 K) on the characteristics of serrated yielding of three commercial aluminum alloys, AA5052, AA5754 and AA5182, was investigated. In the high temperature treatment range, the stress drop (Deltasigma) decreases with increasing thermal treatment temperature. This is the result of an increase in grain size as the thermal treatment temperature increases and can be explained from the solute-dislocation interaction model. For these alloys without any thermal heat treatment after cold rolling and those with a 472 K heat treatment after cold rolling, there is a critical strain before the onset of serrated yielding. The critical strain is larger for those after 472K heat-treatment as compared to those without heat-treatment. This result can be explained by the precipitation of Mg atoms from the solid solution when heat-treated at 472 K. (C) 2003 Elsevier Science B.V. All rights reserved.