Rotary friction welding of Inconel 718-AISI 304 stainless steel dissimilar joint

Nickel-based superalloy Inconel 718 and austenitic stainless steel AISI 304 are joined by rotary friction welding. The changes in microstructure and mechanical properties of the dissimilar joint for solutionising, solutionising + aging, and post-weld aging treatment, with a prior solution heat treatment, are studied. Two distinct microstructural zones, the FDZ (fully deformed zone) and the TMAZ (thermo-mechanically affected zone) are observed in all weldments. The post-weld aged joint sample shows the highest tensile strength and hardness due to the precipitation of gamma ' (Ni-3(Ti, Al)) and gamma('') (Ni3Nb) strengthening precipitates. The solution-treated sample shows the highest yield strength, while the solutionising + aging treatment is found to deteriorate the mechanical properties of the dissimilar joint. The observed changes in the mechanical properties are investigated based on microstructure and electron dispersive spectroscopy.

Automated summary

Nickel-based superalloy Inconel 718 and austenitic stainless steel AISI 304 were joined by rotary friction welding, and the changes in microstructure and mechanical properties of the dissimilar joint were studied under different heat treatment conditions. Two distinct microstructural zones, FDZ and TMAZ, were observed in all weldments. The post-weld aged sample exhibited the highest tensile strength and hardness due to the precipitation of strengthening precipitates. The solution-treated sample had the highest yield strength, while the solutionising + aging treatment deteriorated the mechanical properties of the dissimilar joint. The observed changes in mechanical properties were investigated based on microstructure and electron dispersive spectroscopy.