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 epsilon Al2Cu3 hexagonal phase have been identified. Moire fringes show the interference of {1 11}(Al) with {1 0(-) 1 0}(epsilon Al2Cu3) glide planes and locally small shifts of 1/3{1 1 1}(Al) and 1/3{1 0(-) 1 0}(epsilon Al2Cu3). 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. (C) 2011 Elsevier B.V. All rights reserved.