Additive manufacturing of commercial Al–Zn–Mg–Cu aluminum alloys with mechanical properties comparable to extruded counterparts

The aluminum alloys produced by friction stir based AM were commonly characterized by fine-grains and coarsened precipitates. Abnormal grain growth (AGG) occurred often when the deposited fine-grained aluminum alloys were subjected to a T6 heat treatment, limiting the application of the friction stir based AM technologies and the produced components. In this study, friction surfacing deposition additive manufacturing (FSDAM) were developed to fabricate components of commercial 7075 high-strength aluminum alloys. The effect of post-processing heat treatment on the microstructure and mechanical properties of the fine-grained 7075 aluminum alloys produced by FSDAM were investigated systematically. The new post-processing heat treatment that was able to generate nano-sized precipitates without AGG was developed for the deposited 7075 aluminum alloys. The ultimate tensile strength, yield strength and ductility of the deposited 7075 aluminum alloys were comparable to those of the extruded 7075 aluminum alloys, offering a new solution for additive manufacturing high strength aluminum alloy components cost effectively.