Processing and Characterization of 3D-Printed Inconel-718 Component through Laser Powder Bed Fusion Route for High-Temperature Space Application

3D printing is an advanced manufacturing technology, enabling production of complex shapes by adding material layer-upon-layer. A fuel injection system component designed with Inconel-718 nickel-based superalloy for an advanced rocket propulsion system was realized through Laser Powder Bed Fusion method. 3D printing allowed realizing the complex component having interconnected channels and having minute openings, which are impossible to manufacture by conventional manufacturing methods such as CNC machining. Detailed metallurgical characterization and mechanical property evaluation were performed to qualify the component for space application. The process helped in avoiding multiple piece assemblies for the fuel injection system and developing an integrated component within a short turnaround time. Microstructure evaluation revealed absence of any defects such as porosity, lack of fusion and microcracks. The mechanical properties were evaluated on 3D-printed test coupons in four different orientations along with the component. The fractographs in STA condition in four different orientations revealed a typical ductile fracture with the presence of dimples. Computed tomography of component was carried out and it was concluded that defects > 139 μm were not present, which is the limitation for the thickness of Inconel-718 component scanned. The formation of fine, complex channels and absence of defects > 139 μm as observed in CT, makes the component suitable for complex fuel injection operation for high-temperature space application.