Study on the formation mechanism of functional surface microstructure by ultrasonic vibration assisted laser processing

In this paper, a novel ultrasonic vibration-assisted laser surface processing technology is proposed for preparing microstructures on metal surfaces. Firstly, the formation mechanism of single laser spot on metal surface is analyzed, and the mathematical model of three-dimensional morphology of single crater is derived, the influence of ultrasonic vibration on the crater morphology is studied. Secondly, the influence of ultrasonic vibration on the position distribution of heat affected zone in single laser path is studied. After, the influence of ultrasonic vibration and laser scanning speed on the shape of the laser path is expressed by pushing the overlap rate between the heat affected zones. The calculation results show that the larger ultrasonic amplitude, the greater effect on the curve shape. Finally, the correctness of the calculation and simulation results is verified by experiments. It is observed that ultrasonic vibration can promote the discharge of the melt and provide a new method for changing the surface microstructures. •The mathematical model of the pit formed by a single laser spot is established.•The mathematical model of the over lap rate in the heat affected zones is established.•The relationship between processing parameters and surface structure was described.•The theoretical analysis was verified by experiments and new structures were prepared.