Precipitation processes in Al–Mg–Cu alloys

An investigation of two Al–Mg–Cu-based alloys was carried out in order to identify the precipitating phases at a given aging treatment. Transmission electron microscopy techniques were employed for this purpose. Different types of precipitates were present in each alloy, depending on their Cu:Mg ratio. An attempt was made to study the structure of GPB zones, which were retained in alloys with the lower Cu content after aging at 200 °C for 16 h. An ordering process appears to be associated with the formation of these precipitates. A correlation is made between the precipitation sequence and the strength of the material.