Atomic-scale roles of Zn element in age-hardened AlMgSiZn alloys

• 作者: N.N.Jiao Y.X.Lai S.L.Chen P.Gao J.H.Chen
• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2021,（11）
• 页码范围: 105-112
• 页数: 8页
• 语种: 英文

摘要

Adding alloying elements to improve the performances or the manufacturing processes of Al-Mg-Si alloys has long been a serious issue in developing advanced automotive aluminum materials.The Zn element,among those promising ones,has demonstrated positive alloying effects on Al-Mg-Si alloys.However,the atomic-scale roles of Zn in an age-hardened Al-Mg-Si-Zn alloy have not been adequately understood.Using atomic-resolution electron microscopy,here we report the precise locations of Zn elements in all hardening precipitates involved and their alloying mechanism at the atomic scale when alloying the alloy.Our results show that Zn atoms enter all the major hardening phases to occupy specific featured atomic sites of the original elements,e.g.the Si1 and Mg2 sites in the β'-2 phase,and modify their crystal structures,interfacial structures and morphologies in characteristic manners.It is revealed that for theβ'-phase,Zn atoms occupy unique atomic sites,whereas for other phases,they demonstrate similar behaviors as other additive alloying elements such as Ag and Cu do.