Mechanical and Microstructural Characterization of AISI 410 Stainless Steel–Inconel 625 Functionally Graded Bimetallic Wall Fabricated by Wire Arc Additive Manufacturing

Abstract

This work investigates the mechanical and microstructural properties of a functionally graded bimetallic wall composed of American Iron and Steel Institute (AISI) 410 stainless steel (SS) and Inconel 625, produced by Wire Arc Additive Manufacturing (WAAM). Mechanical assessments, including tensile, impact, hardness, wear, and corrosion tests, were conducted on AISI 410 SS, Inconel 625, and the functionally graded interface region. The interface exhibits strong mechanical performance, showing a tensile strength of 605.79 MPa and an impact energy of 126 J. Hardness Rockwell C (HRC) increases at the interface to 92.5 HRC, compared to 85 HRC in AISI 410 SS and 84 HRC in the Inconel 625 region. Wear testing indicates weight losses of 0.097 g for AISI 410 SS, 0.064 g for the interface, and 0.044 g for Inconel 625, confirming enhanced wear resistance at the graded region. Corrosion evaluation reveals weight losses of 0.007 g for AISI 410 SS, 0.001 g for the interface, and 0.004 g for Inconel 625, demonstrating excellent corrosion resistance at the interface. Microstructural characterization shows uniform, defect-free layer deposition. Inconel 625 exhibits a columnar dendritic structure, whereas AISI 410 SS shows a fine cellular microstructure. Overall, the AISI 410 SS–Inconel 625 functionally graded material (FGM) exhibits superior combined properties suitable for engineering applications.