The microstructure and mechanical properties of a Mg, Ag and Zn micro鄄alloyed Al-3. 48Cu-1. 44Li
(wt%) alloy treated by T8I6 secondary aging were investigated by means of normal mechanical property test, scanning e鄄
lectron microscope(SEM) and transmission electron microscope(TEM). The results showed that, the strength of secondary
aging alloy is improved and the elongation is slightly lowered compared with single aging alloy; the strength increased fur鄄
ther with the third stage aging prolonging. The strengthening phases of the experimental alloy are mainly T1 precipitates with
minor 兹忆and S忆precipitates. The UTS, YS and elongation of the optimum alloy are 613.7, 564.9 MPa and 6.8%, respec鄄
tively. The secondary aging promoted the formation of aging precipitates, especially T1 precipitates,which improved the
strength. Meanwhile, the elongation of the alloy with T8I6 secondary aging is almost not lowered.