| dc.description.abstract | This study investigates the effects of trace Cu on the mechanical properties and stress corrosion resistance of primary Al-Zn-Mg alloys and 100% recycled commercial Al-Zn-Mg alloys through microstructural analysis, tensile testing, slow strain rate testing (SSRT), and polarization potential testing. The primary Al-Zn-Mg(-Cu) alloy serves as a control group in the study, with a comparative analysis conducted on the performance differences between alloys with no Cu addition and those containing 0.2 wt% Cu across varying recycling ratios.
The results demonstrate that the addition of trace Cu significantly enhances the strength and corrosion resistance of both primary and 100% recycled Al-Zn-Mg alloys. Microstructural analysis reveals that Cu addition increases the precipitation of the η’-MgZn? strengthening phase within the α-Al matrix, thereby significantly improving the tensile strength and mechanical properties of the alloy. Furthermore, the addition of Cu raises the Cu content in the η-MgZn? equilibrium phase at grain boundaries, which, in turn, elevates the corrosion potential, reduces the potential difference with the α-Al matrix, and decreases the occurrence of galvanic corrosion, thereby markedly improving the corrosion resistance of the alloy.
However, the presence of β-Fe-rich phases in the α-Al matrix of 100% recycled Al-Zn-Mg(-Cu) alloys slightly reduces ductility and increases the likelihood of pitting corrosion in corrosive environments. Nonetheless, the overall strength and stress corrosion resistance of the 100% recycled and primary Al-Zn-Mg(-Cu) alloys are comparable, underscoring the application potential of recycled alloys.
In summary, the addition of trace Cu not only effectively enhances the strength and corrosion resistance of both primary and recycled Al-Zn-Mg alloys but also significantly improves the overall properties of recycled alloys, providing valuable insights for the industrial application of recycled aluminum alloys.
Keywords: Al-Zn-Mg alloys, recycling ratio, Cu content, stress corrosion. | en_US |