Additive Manufacturing Techniques for Lightweight Structural Components in Aerospace

Abstract

Additive manufacturing (AM) inverts the logic of conventional aerospace fabrication: rather than machining a structure out of a solid billet at buy-to-fly ratios that often exceed 10:1, material is deposited layer by layer only where a component's load path requires it. This article synthesizes the literature on AM for lightweight structural components in aerospace, covering the principal metal AM process families used for flight hardware -- laser and electron beam powder bed fusion, wire-arc and other directed energy deposition variants, and the newer, solid-state cold spray process -- and how each trades build envelope, feature resolution, and deposition rate for the others. We trace the materials science of AM-specific anisotropy, porosity, and fatigue behavior that governs whether a printed part can be trusted with flight loads, and the design methods, principally topology optimization coupled to AM manufacturing constraints, that convert AM's geometric freedom into measured structural mass savings, including case studies reporting a 79% mass reduction on a topology-optimized satellite star tracker bracket, a 40% reduction on a satellite edge insert, and a 62% reduction on a cold-spray-built jet engine bracket. We then examine the qualification and structural-integrity literature that stands between such demonstrations and routine certified use, and close with a discussion of open challenges in cross-process qualification, fatigue design allowables, and design-tool maturity. Read together, the evidence supports additive manufacturing, paired with topology optimization, as a demonstrated and increasingly mature route to substantial aerospace structural mass reduction, with qualification and design-practice maturity, rather than any doubt about the underlying mass-saving potential, as the primary remaining gap.