Microstructure and mechanical properties of Inconel-625 welded joint developed through microwave hybrid heating

Application of microwave energy for processing of bulk metals is effectively utilized to join Inconel-625 plates through hybrid heating technique using Inconel-625 powder as an interface filler material. Post welding characterization of microwave developed joints through X-ray diffraction shows the development of carbides of niobium and chromium as well as intermetallic phases along with the primary gamma-phase face-centered cubic matrix. Microstructural examination reveals the formation of Laves phase along the grain boundaries in the fusion zone. Microwave-induced joints exhibit average microhardness of 245 +/- 20 HV and 0.7% porosity in the fusion zone. Average ultimate tensile strength and flexural strength of the developed joints were estimated at 375 and 377 MPa respectively. Average impact toughness of microwave-induced joints is observed to be 18 J.