Enhanced Surface Topography and Tailored As-Built Microstructure in High-Productivity PBF-LB/M of IN718 Using Ring-Core Beams
Year: 2026
Type: article
Abstract: Laser beam shaping, defined as the spatial redistribution of laser intensity, has emerged as an additional process parameter in laser-based powder bed fusion of metals (PBF-LB/M), offering new opportunities to increase productivity, broaden the process window, and tailor as-built part properties. In Inconel 718 processed with shaped laser beam profiles, the as-built microstructure often exhibits pronounced anisotropy, characterized by coarse columnar grains with a preferred ⟨100⟩ crystallographic orientation along build direction. Moreover, the use of large melt pools generated by shaped laser beam profile, at high scanning speeds can cause material accumulation at scan vector endpoints and stripe overlaps, resulting in surface topography irregularities such as waviness, and elevated edges. Recent studies in high-power PBF-LB/M combined with shaped laser beam profiles redefine part quality beyond high relative Archimedes density and low areal porosity considering smooth top surface roughness and controlled microstructural isotropy. In this study, a systematic PBF-LB/M process parameters optimization of Inconel 718 using different ring-core laser beam profiles is presented. The results demonstrate effective volumetric build rates of approximately 13–16 mm³/s, areal porosity levels below 0.02 %, smooth top surface roughness (Sa < 25 µm), and controlled as-built microstructural anisotropy. Samples with different degrees of microstructural isotropy, ranging from isotropic to semi-isotropic and anisotropic, were successfully produced. Finally, a potential path-planning strategy for high-power PBF-LB/M is introduced to mitigate surface bulging.
Source: Procedia CIRP
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7202265882