Precipitation Of Dispersoids In Al-Mg-Si Alloys With Cu Addition

Nanoscale alpha-Al(FeMn)Si dispersoids in Al alloys play a vital role in improving the recrystallization resistance and mechanical properties of alloys at elevated temperatures. This study investigates the influence of Cu on the precipitation behavior of alpha-dispersoids in Al-Mg-Si alloys during heat treatment at 500 degrees C. alpha-dispersoids in an alloy without Cu addition had rod- or plate-like morphologies. The addition of Cu effectively inhibits the precipitation of alpha-dispersoids through the formation of fine spherical dispersoids, resulting enhanced mechanical properties of the alloy at elevated temperatures. Evidence from high-resolution transmission electron microscopy demonstrated that the rod- or plate-like structures have simple cubic structures, whereas the spherical alpha-dispersoids are coherent with the Al matrix along the [101] zone axis of Al, resulting in finer dispersoids, higher thermal stability, and lower coarsening rates. However, its crystal structure requires further investigation. (C) 2021 The Author(s). Published by Elsevier B.V.