Microstructure of SUS316L Stainless Steel/Inconel 718 Superalloy Functionally Graded Materials Manufactured by Directed Energy Deposition and Powder Metallurgy Methods

Abstract SUS316L stainless steel/Inconel 718 superalloy functionally graded materials (FGMs) manufactured by directed energy deposition (DED) and powder metallurgy using spark plasma sintering (SPS) methods were investigated. The microstructures of the samples manufactured by the DED and SPS methods were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The FGMs sample manufactured by the SPS method was found to be composed of both SUS316L stainless steel and Inconel 718 grains even in the graded zone. In contrast, in the case of FGMs manufactured by DED, mixing of the chemical composition of the raw materials in the melt pool as a result of melting forms a composition of the local region. It can be concluded that DED is effective when a precise gradient is required and the utilization of high-strength components is anticipated.