Abstract: Arc additive manufacturing technology can shorten the production cycle, reduce costs, and realize the rapid prototyping of aluminum alloys, but there are problems that the structure contains more pores and coarse grains. Hot-wire arc additive manufacturing (HWAAM) can effectively reduce porosity and refine grains, further improving the performance of arc additive manufacturing of Al-Cu-Mg-Ag alloys. Hot-wire arc additive manufacturing is employed here to manufacture Al-Cu-Mg-Ag alloy. Their porosity, microstructure, and mechanical property were studied by tensile testing as well as scanning electron microscope and transmission electron microscope observations. Compared with cold-wire structure, hot-wire structure’s porosity decreases by 25 %, the sphere of the pores increases, and the spatial distribution is relatively uniform. The size of the grain is reduced by 30%, and the grain morphology tends to be equal to the axial crystallization. The tensile strength of cold-wire structure is 218 MPa, yield strength is 134 MPa and its elongation after fracture is 3.2%. Upon HWAAM, the mechanical property is improved, with the tensile strength increasing to 242 MPa, the yield strength increasing to 148 MPa, and the elongation after fracture reaching 4.2%. Heat treatment is further employed to tune the mechanical property of Al-Cu-Mg-Ag alloys via HWAAM. After using both solution treatment and aging treatment, the tensile strength reaches 368 MPa and the elongation after fracture decreases to 0.5%. After single aging treatment, its tensile strength reaches 297 MPa, with an elongation after fracture of 2.1%.

Key words: wire arc additive manufacturing, Al-Cu-Mg-Ag alloy, heat treatment, microstructure, mechanical properties