Abstract:Low cycle fatigue(LCF) tests under different total strain amplitudes have been conducted in four aging conditions of 8090 Al-Li alloy. It was found that the cyclic stress response and the LCF lifetime of the alloy varied with the aging conditions and strain amplitudes. The cyclic stress-strain behaviour and fracture mode of Al-Li alloy are closely related to an increasing in the dislocation density, dislocation-dislocation interactions and interactions between the precipitates with dislocations.

Key words: low cycle fatigue cyclic hardening precipilate phase