Effects of lateral and vertical ultrasonic vibrations on the microstructure and microhardness of Stellite-6 coating deposited on Inconel 718 superalloy through laser metal deposition

In this research work, Stellite-6 was deposited on an Inconel 718 substrate via laser metal deposition (LMD) process. Lateral and vertical ultrasonic vibrations were applied during the LMD process at 150 W and 250 W to achieve improved properties. The resultant coatings were evaluated by scanning electron microscopy (SEM) equipped with an energy dispersive spectroscopy (EDS) analyzer and optical microscopy. Also, the microhardness values of two samples (without vibration and with vertical vibration) were measured. The results showed that applying ultrasonic vertical vibrations led to significant changes in the microstructure of the coatings and the coating/substrate interface i.e. a better distribution of alloying elements of the coating was achieved, the number of the secondary arms increased, and the porosity percentage decreased significantly. Moreover, the microhardness value in the sample synthesized at 150 W and under vertical vibrations were higher than that in the sample produced without vibrations.