Effect of Er and Si co-microalloying on mechanical properties and microstructures of AlCuMg alloys

The effect of Er and Si on the evolution of precipitates in Al-Cu-Mg alloys during elevated temperature exposure was investigated. The Er segregation in 0'-Al2Cu precipitates and Si/ Mg co-segregation at the interfaces of 0r/Al matrix are experimentally observed in Al-Cu -Mg-Si-Er alloy, which finally contributes to the heat resistance of the Al-Cu-Mg-Si-Er alloy. Si enhances formation of the Q'' phases as nucleation sites for the 0' phases, resulting in a refined distribution of 0' phases. Al-Cu-Mg alloy with high strength as well as high thermal stability is obtained by co-adding Er and Si. The high-temperature yield strength (YS) of Al-Cu-Mg-Si-Er alloy at 225 degrees C are increased by 37 MPa compared with that of Al -Cu-Mg alloy. Simultaneously, the addition of Er significantly increases the elongation of Al-Cu-Mg-Si-Er alloy.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).