Wire and arc additive manufacturing of 316L stainless steel/Inconel 625 functionally graded material: development and characterization

In this work, a 316L stainless steel to Inconel 625 functionally graded material (FGM) was built using different deposition strategies (named as direct and smooth-type interfaces) by Twin-Wire Arc Additive Manufacturing (T-WAAM). This combination of materials is interest in chemical plants, oil & gas, nuclear applications, where high corrosion wear resistance are essential requirements. Although these properties superior 625, replacing with strategic regions structural components can reduce the overall costs parts’ weight. Both smooth transition interfaces were tested characterized. Microscopic analysis revealed that each interface as-built samples had an austenitic matrix, every sample well bonded free defects. Different types microstructures evolved at due distinct gradients composition. Synchrotron X-ray diffraction measurements showed smooth-gradient produced secondary phases, such δ-phase (Ni 3 Nb) carbides, not present strategy. Overall, FGM interface, which experienced higher strengths elongations upon failure. Moreover, neutron lower residual stresses developed than gradient FGM.