Achieving balanced mechanical properties in Al–Mg–Si–Cu–Zn alloys via Mg content-driven multilevel ordered precipitation

作者：Liang Zhu, Qihang Chen, Junfei Xu, Xinsheng Yang, Aixin Feng, Shiyue Guo, Mingxing Guo, Jishan Zhang, Huajun Cao, Kun Li · 发表于：Journal of Materials Research and Technology · 年份：2025 · DOI：10.1016/j.jmrt.2025.11.193 · 被引用次数：3 · 研究领域：Aluminum Alloy Microstructure Properties、Microstructure and mechanical properties、Magnesium Alloys: Properties and Applications

Al-Mg-Si-Cu-(Zn) alloy, recognized for its rapid age-hardening characteristics, holds significant promise for automotive sheet applications. However, achieving an optimal balance between strength and ductility by modulating the precipitation behavior remains a formidable challenge. Here, we have systematically elucidated the regulatory influence of Mg content on the precipitation behavior and mechanical properties of Al-Mg-Si-Cu-Zn alloys through multilevel ordered precipitation. The results illustrate the dual role of Mg in simultaneously refining grains and steering precipitation pathways. During isothermal aging at 120 °C, the optimal Mg content (1.69 wt.% Mg) favors β'' phase nucleation, while excess Mg shifts the precipitation toward clusters or pre-η' phases. At 185 °C, higher Mg content increases the density and size of β'' phase precipitates, strengthening the alloy, until 2.87 wt.% Mg triggers coarse η phase formation and strength loss. This demonstrates that excess Mg suppresses β'' phase formation, whereas in lean Mg alloys, β'' phase is highly sensitive to the aging temperature. Consequently, by strategically balancing the aging temperature and Mg content, a desirable combination of properties can be attained in Al-Mg-Si-Cu-Zn alloys. This finding offers theoretical guidance for developing next-generation automotive aluminum sheets with high strength and high ductility.