SURFACE ROUGHNESS AND GEOMETRY EFFECTS ON THE FATIGUE BEHAVIOR OF SELECTIVE LASER MELTED INCONEL 718 AT 650 degrees C

Inconel 718 specimens with the build thickness of 1.3 mm and 3.3 mm were manufactured by selected laser melting and subsequently heat treated through homogenization plus double aging. These specimens in the un-machined and machined states were fatigued at 650 degrees C. The profile of surface defects of the specimens was statistically characterized using 3D-high resolution transmission X-ray tomography (3D-XRT) technique. Furthermore, the finite element (FE) simulations were conducted to reveal effects of the defect shape on fatigue properties. The findings reveal that both academic and industrial community for additive manufacturing may need to pay more attention to control the shape of surface defects of additively manufactured parts by tailoring the process parameters.