Equiaxed microstructure formation by ultrasonic assisted laser metal deposition

Laser metal deposition (LMD) provides a unique approach for surface modification and additive manufacturing. It typically leads to the formation of columnar crystal structures and defects in metals. In this study, ultrasonic vibration was applied on LMD of 316L. Contrastive studies show that columnar microstructures were observed without ultrasound, while equiaxed crystal structures were found with ultrasonic vibration. The reasons to generate the equiaxed microstructures were discussed. The results provide a feasible method for improving the quality of additive manufactured parts.