Pre-deformation effect on stress-relaxation ageing behavior and mechanical properties of AA2219 alloy

Abstract

The effects of pre-deformation on the stress-relaxation ageing behavior and associated mechanical properties of AA2219 alloy are studied. The result shows that with the increase of pre-deformation, the amount of relaxed stress increases accordingly. The stress exponent indicates that the deformation mechanism is primarily controlled by dislocation climb for the samples with 0%, 3% and 6% pre-deformation and dislocation glide for the 9% and 15% pre-deformed ones. Microstructural observation shows that the dislocations induced by pre-deformation facilitate the formation and number of strengthening precipitates, thus enhancing the strength. However, when the pre-deformation gets to 15%, the strength appears to decrease due to the presence of coarse precipitates and precipitate free zone inside the grain.