Characterization of microstructure, defects, and mechanical properties of additive manufactured nickel-base superalloys

Due to the excellent high-temperature performance of nickel-based superalloys and the need for complicated geometries and simple repairs, methods of creating nickel-based superalloy parts by additive manufacturing (AM) are currently being developed. In this study, Laser Engineered Net Shaping (LENS) is used as the AM process to create samples, and Inconel 718 is used as the nickel-based superalloy. LENS is an AM method that uses a laser to selectively melt metal powder, while introducing additional powder in order to add to the volume of the melt pool. This process is commonly used for part repair; however, the processing parameters and resulting structure and properties of the material are not yet fully understood. This study characterizes Inconel 718 samples fabricated using LENS printing using optical microscopy, energy-dispersive X-ray spectrometry, scanning electron microscopy, electron backscatter diffraction, and Vickers microhardness, and proposes explanations for the results based on the printing process