Ultra-fast bake-hardening response of Al-Mg-Si-Cu-Zn alloys with the assistance of heterogeneous nucleation

Mg-Si clusters or precipitates can make Al-Mg-Si alloys stronger, but the low bake hardening response severely restricts their wide application in the automotive field. Here, we report a new strategy to significantly enhance the bake-hardening response of AlMg-Si-Cu-Zn alloys to the highest value of 167 MPa, compared with values of traditional 6xxx series alloys (such as, AA6016, AA6111 and AA6022). The ultra-fast bake-hardening response is mainly obtained by the synergy of homogeneous/heterogeneous nucleation of Zn-containing precipitates during the heat treatments. The process discovered here is amenable to large-scale automotive industrial production at low cost, and might be applicable to other Al alloy systems.(c) 2022 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/).