Additive manufacturing of thin-walled SS316L-IN718 functionally graded materials by direct laser metal deposition

Functionally graded materials (FGMs) are a good response to those advanced applications that service requirements diverse and require high performance. Additive manufacturing (AM) technology, with its many advantages, including flexibility for complex geometries near-net-shape integration, has attracted special attention in the development of FGMs. In this research, solidification behavior microstructure evolution laser additive thin-walled stainless steel 316L-Inconel 718 have been studied help concepts welding metallurgy, according common principles processes. For purpose, optical electron microscopy techniques, X-ray energy dispersive spectroscopy, microhardness measurement were used along build direction FGMs different transition designs. Microstructure evaluation showed due re-melting layers, despite increased undercooling direction, morphological occasionally occurred periodically between modes, thermal accumulation, coarser is formed final layers. addition, chemical analysis, it was observed mixing adjacent layers caused by dilution led deviation composition distribution from desired design. Also, microsegregation some elements during non-equilibrium process secondary phases such as carbides intermetallic compound Laves, which can an adverse effect on mechanical properties structure. However, variations cross-section samples gradation dissimilar structure effectively bring closer together therefore be very useful improving life.