Optimizing Wire Arc Additive Manufacturing Strategies for the Repair of Thin-Walled 2219 Aluminum Alloy Aerospace Component Using a Cycle Step Approach

The aerospace sector is increasingly prioritizing component repair over replacement as a sustainability strategy, driving demand for additive manufacturing solutions capable of restoring complex metallic geometries. Wire Arc Additive Manufacturing (WAAM) via GMAW offers high deposition rates and strong metallurgical bonding, yet its application to thin-walled structures and crack-susceptible alloys remains largely unresolved. This study presents a novel GMAW-WAAM repair methodology for an AA2219 aluminum-copper orthogrid aerospace component, characterized by thin walls (2-4 mm), a thin substrate (3mm), and structurally critical wall intersections. AA2219/2319 presents an exceptional challenge for WAAM due to its high susceptibility to hot cracking and hydrogen porosity. By leveraging CMT Cycle step technology combined with a controlled, intermittent dot-by-dot deposition strategy with optimized pauses between dots, this approach mitigated issues inherent to thin geometries, such as heat accumulation, collapse, and burn-through. For wall intersection repair, overlapping curved deposition paths proved the most effective strategy by avoiding arc start/stop points within critical zones. Microstructural characterization of the deposited material revealed no hot cracking, no significant porosity, or major defects, confirming the sound metallurgical integrity of the repair despite the challenging thermal conditions imposed by the thin-walled geometry and the crack-susceptible nature of AA2XXX alloys. These findings validate GMAW-WAAM as a viable repair route for thin-walled aluminum aerospace components and establish process guidelines applicable to similarly constrained geometries.