Experimental research on the influence of ultrasonic vibrations on the laser cladding process of a disc laser

Abstract

Disc lasers have a wide range of applications in laser cladding due to a series of advantages such as good beam quality. The cladding layer formed by the disc laser in laser cladding is prone to microcracks, pores and other microscopic defects, which seriously affects the promotion of this technology. Ultrasonic vibration can generate high-frequency and low-amplitude vibrations, which actively affect the formation of the microstructure during the solidification of the cladding layer. They can effectively reduce the formation of microscopic defects. This paper builds an ultrasonic-assisted laser cladding system platform based on a disc laser. We cladded 316L powder onto an ASTM 1045 steel substrate for multiple laser cladding experiments, and performed microscopic characterization and analysis of the cladding layer. The result shows that ultrasonic vibrations can effectively refine the bottom and top microstructures of the cladding layer, especially the morphology of the dendrite arms. The phase structure did not change under different ultrasonic amplitudes. Ultrasonic vibration changes the direction of heat flow inside the molten pool, causing the crystal orientation to change from a (220) crystal orientation to a (111) crystal orientation. This research will provide an important theoretical basis for the precise control and optimization of the cladding process and reduction of the formation of microscopic defects.