Microstructure and mechanical properties of hybrid additive manufactured dissimilar 17-4 PH and 316L stainless steels

Abstract Hybrid metal additive manufacturing is a novel way of combining the advantages of different manufacturing methods. It offers the freedom of fabricating functional parts with varying requirements such as size and complexity, overcoming the need for additional joining operations. On the other hand, combining dissimilar materials enables the route for obtaining different properties such as mechanical strength, high temperature and corrosion resistance in a single part body. In this study, wire arc additive manufacturing (WAAM) and laser powder bed fusion (L-PBF) technologies were combined utilizing dissimilar metals for each process. Deposition of AISI 316L stainless steel on previously L-PBF manufactured 17-4 PH stainless steel part was successfully executed using WAAM process. Microstructural observations showed five different zones in the as-built state whereas a uniform microstructure was obtained following the heat treatment as confirmed by hardness measurements. Tensile tests were conducted on the specimens extracted from the L-PBF/WAAM interface and the results showed a ductile fracture from the WAAM region, validating the strength of the interface. The tensile test results exceeded the standard strength requirements with a minor decrease in ductility.