Laser cleaning assisted wire arc additive manufacturing of aluminum alloy thin-wall through synchronous wire-powder deposition

Due to the interference of ambient wind on arc burning and droplet transfer, wire arc additive manufacturing (WAAM) of aluminum alloy in field environment is hindered. The gas-slag joint protection by synchronous feeding of AlSi5 wire and mixed powder of 90Mg-5TiO2-5NaF (wt.%) was introduced. It was found the wind resistance for the stable deposition of thin-wall could be improved from 1.5 to 3.5 m/s. The added Mg benefited to refine the grain size by 21% and promote the formation of Mg2Si, which improved the mechanical properties by induced solid solution-precipitation strengthening effects. Furthermore, with the assistance of laser cleaning, the porosity of thin-wall deposited at ambient wind speed of 3.5 m/s was reduced from 54.9% to 28%. These improvements increased the ultimate tensile strength and elongation to 166 MPa and 3.7%, reaching 98.2% and 31% of the WAAM at indoor windless environment respectively.