HRTEM and HAADF-STEM of precipitates at peak ageing of cast A319 aluminium alloy

► This paper examines the nature of precipitates formed in cast Al-Cu-Si alloy after solution treatment at 500 ± 5 °C for 8 h and ageing at 170 ± 5 °C for 24 h. ► High-resolution TEM imaging and HAADF-STEM imaging have been applied to analyze the precipitated particles. ► Nano-beam electron diffraction (NBED) has enabled the precipitates at the peak aging to be identified as θ”-Al3Cu and θ'-Al2Cu.