Synergistic strengthening by βand i′ phases in Al-Mg-Si-Cu-Zn alloys

Based on the concepts of high alloying degree and two-phase synergistic strengthening, a new strategy is provided to increase the low strength of 6000-series (Al-Mg-Si) alloys. By increasing the Mg content and adding Cu and Zn into Al-Mg-Si alloys according to phase calculations, beta and i' phases were precipitated in the alloy, as shown by TEM and APT results. This is different from the single-phase precipitates typically observed in Al-MgSi-Cu-Zn alloys. The strength of the two-phase synergistically precipitated alloy was higher than that of the single-phase precipitated alloy. Specifically, the yield strength and tensile strength increased by 18.1 and 17.7 MPa, respectively.

Automated summary

By increasing the Mg content and adding Cu and Zn into Al-Mg-Si alloys, beta and i' phases were precipitated in the alloy, leading to a synergistic strengthening effect and higher strength compared to single-phase precipitates. Specifically, the yield strength and tensile strength increased by 18.1 and 17.7 MPa, respectively.