Abstract: Small-angle X-ray scattering (SAXS) was used to study the precipitation behavior of the δ′phase in 1420 alloy treated by aging-retrogressionreaging. The results show that the transition interfacial layer exists between the δ′ phase and the matrix after reaging for 5 h, but the transition interfacial layer disappears after reaging for 48 h. The gyration radius of the δ′ phase particles, R_G was 9.32 nm for aging 80 h and 8.27 nm for reaging 80 h, respectively. This suggests that the δ′ phase particles coarsen is much slower during reaging treatment compared with that of aging treatment. With the reaging time increase, the δ′ phase grain size is not the same. 

Key words: Al-Li alloy, aging-retrogression-reaging, radius of gyration, small-angle X-ray scattering