Effect of Welding Torch Mode on Heat Input, Microstructure, and Mechanical Performance of Inconel 625 via Wire-Arc-Directed Energy Deposition

Cold metal transfer-based wire-arc directed energy deposition offers high molding efficiency and the capability to produce large, complex structural components. However, the grain structure and mechanical performance of the deposited parts are significantly influenced by the thermal history during deposition. This study prepared Inconel 625 samples using two different torch modes (vertical and tilt). The effects of two torch modes and build heights on the molten pool temperature are investigated, and the solidification structure and mechanical performance of the parts at various locations are analyzed. Results show that the deposited samples primarily consisted of columnar dendrites growing epitaxially along the deposition direction, with Laves phase particles distributed in blocks and chains among the dendrites. Tilting the torch contributed to grain refinement and reduced Laves phase precipitates, resulting in samples with high strength. Additionally, the tensile performance of the deposited samples exhibits anisotropy.