Microstructure tuning enables synergistic improvements in strength and ductility of wire-arc additive manufactured commercial Al-Zn-Mg-Cu alloys

It remains challenging to achieve attractive mechanical strength and ductility in commercial 7xxx alloys fabricated by wire-arc additive manufacturing (WAAM). Here, we combine WAAM processing with solution artificial aging treatments functionalise their inherent age-hardening capabilities via microstructure controlling. The as-deposit 7055 alloy shows a heterogeneous bimodal grain size distribution, the primary metallurgical defects are spherical gas pores an inter-layer distribution. Upon optimised T6 temper (470°C/2 h for treatment 120°C/65 aging), nano-sized platelike η’ precipitates generated, tensile boosts from ∼226 MPa ∼562 MPa. Evident yielding uniform plastic deformation is also mediated temper, yield > 500 fracture strain 5%, which comparable conventional wrought alloys. This work provides insight into tuning achieving excellent properties.