A holistic analysis of laser powder bed fusion process parameters for Inconel 625 superalloy: microstructural features and mechanical performance

Abstract

Abstract This study delivers a comprehensive investigation into the combined effects of primary process parameters (PPPs) on the mechanical properties, microstructure, and melt pool geometry of Inconel 625 fabricated via laser powder bed fusion (L-PBF). These PPPs include scanning speed, layer thickness, build direction, and laser power. In contrast to prior studies focusing on isolated parameters, a systematic, holistic analysis that uncovers critical process–property relationships was provided. The optimized batch achieved an unprecedented combination of ultimate tensile strength (UTS) of 828.9 MPa and 36% elongation, surpassing typical L-PBF outcomes, attributed to precise PPP control (350 W laser power, 1400 mm/s scanning speed, 30 µm layer thickness, and vertical build direction). Fractographic analysis revealed a novel transition from ductile to brittle fracture with increasing scanning speed, while a strong <100> cubic texture enhanced mechanical performance through epitaxial growth. These findings offer a robust framework for tailoring L-PBF processes to meet stringent application demands in aerospace, automotive, and biomedical fields, advancing the frontier of additive manufacturing.