Enhancing the mechanical properties ofdirected [!] energy deposition arc (DED-Arc) via processing innovations

Directed Energy Deposition (DED) processes offer the advantage of producing larger parts with higher deposition rates compared to Powder Bed Fusion (PBF) additive manufacturing (AM). However, DED typically results in simpler geometries and lower resolution. When using Wire and Arc-based DED, even larger components can be manufactured at an accelerated rate, but the higher heat input may lead to undesirable microstructures, adversely affecting mechanical properties. To ensure defect-free depositions, precise process control is essential, including optimizing deposition paths, regulating inter-layer temperature, and maintaining a consistent nozzle-to-layer distance. One effective approach to improving material integrity is the application of in-situ vibrations during deposition. This technique helps reduce porosity and grain size while also enhancing surface waviness and mitigating residual stress buildup. Further refinement of material properties can be achieved through appropriate thermo-mechanical processing, leading to mechanical characteristics comparable to conventionally produced steel. This paper explores the impact of in-situ vibrations and heat treatment through case studies, analysing their effects on surface waviness, residual stress distribution, porosity, microstructure, grain size, mechanical properties, and fracture toughness. The findings demonstrate the significant benefits of these process enhancements in improving the mechanical performance of DED-fabricated components.