Novel method of additive manufactured functionally gradient materials using multi-component stranded welding wires

In this work, the stranded welding wires (SWWs) were firstly used to fabricate functionally gradient materials (FGMs) by cold metal transfer process. A comprehensive assessment of this method was conducted in the 316L/Inconel718 system. The FGM was successfully fabricated with an inherently high depositing rate (70.7 g/min). Due to the unique molten stirring effect of SWWs, the as-printed FGM has shown excellent forming quality (low porosity value of 0.00378 %) and strong interfacial bonding which is achieved by the smooth compositional transition and heterogeneous microstructure at the interfacial zone. Combined with the compositional and structural similarity, the strong bonding fully unleashes the deformation potential of the stronger part in FGM, achieving a unique bimodal local strain distribution and outstanding fracture elongation (34 ± 4 %). This work can provide a new option for the fabrication methods of FGMs.