Figure 2

STEM images of precipitates in the matrix showing the distribution and morphology of the precipitates. (a) GP zones and plate-like η′ precipitates are observed as the predominant precipitates, which are commonly observed in T6 tempered Al-Zn-Mg alloys. (b) An enlarged image of one portion in (a), the majority of the plate-like η′ precipitates (diameter ~58.2 nm) are distributed on or near the dislocation lines the dislocation lines in a typical grain interior. (c,d) The high number density of GP zones (diameter ~3.7 nm) distribute homogeneously in the matrix.