High resolution transmission electron microscopy study on the development of nanostructured precipitates in Al–Cu obtained by mechanical alloying

[Display omitted] ► Development of defect structures and nanoprecipitates after 10 h of mechanical alloying in Al–Cu system. ► Defects act as nucleation sites of the ɛAl 2Cu 3 phase. ► Incoherent and semicoherent precipitates are identified by TEM–HRTEM. ► Moiré patterns are associated to the ɛAl 2Cu 3 phase. Aluminum alloy 2014 is used to obtain nanostructured powders via mechanical alloying. The evolution of the diffusion processes is observed by the development of defect structures and nanoprecipitates after 10 h of milling. The characterization includes analytical and high resolution transmission electron microscopy. Dislocations associated with different Al/Cu ratio affect the material. These defects act as nucleation sites where precipitates of the ɛAl 2Cu 3 hexagonal phase have been identified. Moiré fringes show the interference of {1 1 1} Al with { 1 0 − 1 0 } ε Al 2 Cu 3 glide planes and locally small shifts of 1/3{1 1 1} Al and 1 / 3 { 1 0 − 1 0 } ε Al 2 Cu 3 . Changes in the Al/Cu ratio lead to the formation of other solid solutions identified in the Cu rich area and could correspond to transition phases.