Support-Free Fabrication of Inclined and Suspended Thin Walls for Al-Cu-Mg-Ag Alloys via Wire Arc Additive Manufacturing

This study investigates wire arc additive manufacturing (WAAM) for fabricating large-size unsupported Al-Cu-Mg-Ag alloy structures. The fabricated structures include Z:X = 1:2 tilted, Z:X = 1:1 tilted, and horizontal thin walls. By optimizing wire feed speed, X-axis offset distance, and heat input, the stable manufacturing process of large-size overhanging structures were obtained. The presence of gas pores distributed in interlayer remelted zones significantly degraded the mechanical properties of the horizontal thin wall. Among these three suspended configurations, the 1:2 tilted thin wall exhibited optimal tensile properties: 172.3 MPa transverse yield strength, 286.4 MPa tensile strength, and 4.8% elongation. In comparison with the maximum 45° tilt angle reported in present studies, this study expands the tilt angle of WAAM unsupported structures to 90° through process optimization, and the width was increased to 80 mm, providing a promising solution for the fabrication of large-size complex components.