Tailored microstructure and robust joint of Inconel 718/316L bimetallic multi-material fabricated by selective laser melting

Abstract

In this study, selective laser melting (SLM) technology was used to fabricate Inconel 718/316L bimetallic multi-material with robust bonding strength, and a deep insight into the microstructural morphology, mechanical property and its strengthening mechanism of the joint was taken. The transition region with a wide of approximately 150 μm was defined and showed a dominating columnar region which was embedded in dispersed Laves phase occupied the molten of Inconel 718 closed to the joint. X-ray diffraction (XRD) pattern detected the strong peaks of γ', γ'' and a weaker peak of d phase precipitates. Electron backscatter diffraction (EBSD) analysis showed that a distinct grain coarsened region existing and Inconel 718 region had a strong fabric texture with a <001>// Z (BD) orientation. The shear strength of the as-built joint was calculated to be 449.5 MPa, which was comparable to the nickel/steel multi-materials formed by other traditional processing technologies.