Arc Oscillation for Microstructural and Geometric Control of Solids Produced by WAAM

Wire arc additive manufacturing (WAAM) is an additive technology with several advantages, such as a high deposition rate, the possibility to manufacture metallic materials, a very low incidence of porosity and excellent mechanical properties. However, there are challenges in WAAM, like the uncontrollable grain growth (due to the prolonged exposure to high temperatures) and the accumulation of impurities or decrease in toughness (due to preferred crystallographic orientation and the grain growth mechanism). These issues are relevant for many materials like steel, aluminium, titanium, and nickel alloys. This work aimed to use arc oscillation in steel that could break this unrestrained grain growth, resulting in a more refined grain structure. The components were characterised morphologically, geometrically, and microstructurally, and the oscillation resulted in microstructures that were equally or more refined than the base material.