Large-size ultra-high strength-plasticity aluminum alloys fabricated by wire arc additive manufacturing via added nanoparticles

Wire arc additive manufacturing (WAAM) is a potential technology gradually applied in the aerospace, automobile, and military fields due to its advantages of high deposition efficiency, low manufacturing cost, and unrestricted manufacturing space. However, it is still challenging to fabricate large-size high-performance aluminum alloys using the WAAM method. Here we introduced TiC nanoparticles into the AA7075 wire to improve the performance of Al–Zn–Mg–Cu alloys fabricated by WAAM. TiC nanoparticles tended to be incorporated with the second phases on the grain boundary and strengthened these phases. Besides, TiC nanoparticles can as the heterogeneous nucleation sites for the Al matrix due to the small lattice mismatch between them, resulting in refined grain. Finally, the large-size TiC/AA7075 part was fabricated by optimized manufacturing processes. Compared to AA7075 samples, the TiC/AA7075 samples showed fine equiaxed grains and strengthened second phases, as well as superior (strength ∼ 435 ± 10 MPa, elongation ∼ 7.8 ± 0.8% for the deposited state) and isotropic mechanical properties. The outstanding properties are comparable to those of heat-treated Al–Zn–Mg–Cu alloys fabricated by WAAM in existing studies. This method can be widely applied in the WAAM of aluminum alloy to improve the microstructure, and it provides a novel strategy for manufacturing large-size high-performance aluminum alloy.