Microstructural and mechanical properties of resistance spot weld of Inconel 625 supper alloy

This study was carried out to evaluate the microstructural and mechanical properties of resistance spot-welded Inconel 625 alloy. The effects of welding current, applied force, and holding time of resistance spot welding (RSW) process were investigated by optical microscopy (OM) and scanning electron microscope (SEM) images, microhardness tests, and also tensile shear tests. Microstructural investigations showed that the nugget structure consisted of homogenous columnar dendrite structure, which epitaxially grew along the electrode direction, and the microstructure of the heat-affected zone (HAZ) included a fine-grain recrystallized zone (FRXZ), coarse-grain recrystallized zone (CRXZ), and recovery zone (REZ). The effects of welding parameters on the mechanical properties of the spot weld in terms of peak load, fracture energy, and failure mode were investigated.