Investigation of dealloying of S phase (Al2CuMg) in AA 2024-T3 aluminium alloy using high resolution 2D and 3D electron imaging

High-resolution 2D and 3D electron microscopy have been employed to investigate the dealloying of S phase (Al2CuMg) particles in an AA 2024-T3 aluminium alloy. Preferential dissolution of magnesium and aluminium produced a sponge-like remnant with nanosize porosity and a copper-rich remnant network. The dealloyed S phase remnant retains a tetragonal structure with a smaller lattice parameter than the S phase. Metallic copper nanoparticles, constituting 4-8% of the dealloyed remnant, are present at the intersections of remnant branches. At the surface of the remnant, a copper layer of similar to 2 nm thickness is formed, which terminates further dissolution of the less noble elements. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license