Evaluation of different dynamic point melt scanning strategies on microstructure evolution for IN718 bulk parts fabricated by EB-PBF

Metal Additive Manufacturing (AM) is reshaping modern manufacturing by enabling complex, lightweight designs, particularly in aerospace and defense sectors. However, issues like microstructural anisotropy remain a key challenge. Although post-processing methods such as HIP and other heat treatment schedules can address these issues, they are often costly and time-consuming. While Electron Beam Powder Bed Fusion (EB-PBF) helps in reducing residual stress in AM-fabricated metals and alloys, directional grain growth and anisotropy continue to persist. This study focuses on the EB-PBF fabrication of a high-performance nickel-based superalloy Inconel 718 by applying four, point-based melt scanning strategies: A randomized point melt (ST1), single directional shifted point melt (ST2), a snake patterned point melt, with 5 mm intersection (ST3), and a single directional point melt with 5 mm intersection (ST4); under two identical energy modes. EBSD analysis revealed that the scanning strategy has a more dominant effect on grain morphology and texture than the method of energy input. ST1 and ST2 promoted fine, equiaxed grains, while ST3 and ST4 resulted in strong <001> columnar structures. Mixed-strategy samples further validated the scan path influence. These results demonstrate the potential of scanning strategies to control microstructural anisotropy in AM fabricated parts.