Strain aging phenomena in aged Al-4.5Cu alloys and its computer simulation by a strain-softening model

A strain aging test was conducted at room temperature in aged Al-4.5Cu alloy. The stress-strain curve during restraining exhibited a peculiar shape (the stress plateau). Both the strain rate and the aging time strongly affected the aging phenomena. Two characteristics, the stress increase (the difference in the stress between before and after aging) and the transition strain (the strain during the stress plateau) were measured. The shape of the s-s curve and the two characteristics were successfully explained by phenomenological theory based on the strain-softening model constructed to explain the Portevin-LeChatelier effect.