Wire arc additive manufacturing of a large axisymmetric AA2319 aluminum alloy component: Feasibility, characterization, and post-processing

This study investigates the fabrication, non-destructive evaluation, and post-processing of a large AA2319 aluminum alloy ring manufactured using wire arc additive manufacturing (WAAM). Single-track macrostructural analysis revealed that welding currents of 130–140 A produced wider, well-diluted beads, whereas lower currents (90–110 A) resulted in interfacial cracking. Comprehensive non-destructive evaluation combining radiographic testing (RT) and ultrasonic testing (UT) identified porosity, lack of fusion, and inclusions as the dominant defects. Among the inspected regions, the DG sector exhibited the highest structural integrity, with isolated porosity in the range of Ø0.5–1.0 mm, while the AD sector was predominantly unacceptable due to clustered porosity and fusion defects. Mechanical testing revealed pronounced anisotropy in the as-printed condition, with radial specimens exhibiting a yield strength (YS) of 139 MPa, an ultimate tensile strength (UTS) of 220 MPa, and an elongation of 6.4%. Cold-compression-assisted heat treatment significantly enhanced mechanical performance, increasing the radial YS to 350 MPa and UTS to 435 MPa, outperforming interlayer hammering and laser shock peening, albeit at the expense of ductility, which decreased by approximately 50%. Fractographic analysis identified pores and second-phase particles as primary crack-initiation sites, while heat treatment promoted a predominately transgranular fracture mode. The results demonstrate that cold-compression-assisted heat treatment is an effective and scalable post-processing strategy for enhancing the structural performance of large WAAM-fabricated aluminum alloy components.