Effect of ultrasonic vibration on the microstructure and microhardness of laser cladding Fe-based crystalline/amorphous composite coatings

The laser cladding technique with and without ultrasonic vibration was employed to prepare Fe-based crystalline/amorphous composite coatings and the effect of ultrasonic vibration on the evolution of microstructures and microhardness was investigated via SEM observation and microhardness testing. The results show that, during the laser cladding process assisted with ultrasonic vibration, the content of amorphous phase is increased by 1.4 % and the growth of columnar crystals at interface is inhibited. The average length of columnar crystal at interface is measured to be around 17.2 ± 5.1 μm which is diminished by 35.8 %, and the microhardness of coating is about 866.2 ± 57.5 HV0.2 which is improved by 27.9 % compared to that without ultrasonic vibration.