Investigation of microstructural, dynamic mechanical and high temperature corrosion behaviour of CMT-deposited Nickel Alloy 718 on Stainless Steel 304

Nickel Alloy 718 (NA718) is hardfaced over Stainless Steel 304 using Cold Metal Transfer process with sinewave weaving. The hardfaced layer exhibited an optimum dilution of 17.3%. Microstructural study depicts the grain transitions from columnar to fine equiaxed. Fine grains and intermetallics are aided to enhance the microhardness upto 66.29% than the substrate. The dynamic mechanical analysis reveals that NA718 offers better damping characteristics. Intermetallics and secondary phases serve as nucleation points for the development of voids and pores. It contributes to the energy dissipation leads to better thermal and dynamic stability. NA718 exhibits lower weight gain (0.0473g) with a smoother corrosion morphology and reduced pit formation, which improves its superior oxidation resistance.