Effect of Power Input on Metallurgical and Mechanical Characteristics of Inconel-625 Welded Joints Processed Through Microwave Hybrid Heating

Abstract

In the present study, welding of Inconel-625 through the use of microwave hybrid heating (MHH) has been achieved at two power levels 600 W and 900 W in a low-cost home microwave oven. Nickel-based powder EWAC was used as filler interface between faying surfaces. Effect of power variation on the metallurgical and mechanical characteristics of the microwave welded joints has been investigated. Developed joints were characterized through XRD, optical microscope, SEM, universal testing machine and Vickers microhardness tester. XRD study of the weld zone indicated the formation of various carbides and intermetallics. Joint microstructures witnessed a completely fused weld interface without any interfacial cracks. EDS analysis of the joint microstructure revealed lesser amount of segregation of niobium and molybdenum with the specimens developed at 600 W which could be attributed to the lower heat input associated with 600 W power that also resulted in fine grain structure. Further, the specimens processed at 600 W exhibited better tensile and flexural properties when compared to their counterparts produced at 900 W power. Fractography study of the specimens revealed a combined ductile and brittle fracture. 2019, The Indian Institute of Metals - IIM.