The behaviour of copper at the nano-scale in an Al-Zn-Mg (Cu) alloyTuesday (05.11.2019) 14:20 - 14:40 Part of:
High strength 7xxx aluminium alloys used in sector aerospace sector undergo thermo-mechanical processing to enhance material properties and behaviour in service. The nano-scale distribution of alloying elements at strengthening precipitates η’ (M’) and η (M) is studied in microstructures of commercially processed AA7010 alloy. Inhomogeneous distributions of copper, zinc and magnesium are exposed, revealing copper rich precipitate-matrix interfaces at strengthening precipitates in the over aged condition and highlighting the previously unknown behaviour of copper during over aging. High resolution energy dispersive spectroscopy (EDS) accompanies high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), to highlight changes in microstructures and alloying element distribution at the nano-scale after different thermal treatments.