Investigation on microstructure and mechanical properties of Fe-based amorphous coatings prepared via laser cladding assisted with ultrasonic vibration

Fe-based amorphous coatings were deposited on 20# mild steel using laser cladding assisted with ultrasonic vibration under different ultrasonic powers from 0 W to 1000 W. When the ultrasound is introduced into the molten pool, it can increase the maximum temperature and life cycle and promote the solute exchange at the bottom of the molten pool. While it has little effect on the molten pool top's temperature field and element distribution. With increasing ultrasonic power, the gradient crystallization structure between the substrate and the amorphous coating increases from 46 μm to 81 μm and appears as a changed wave. The cracking trend of the coating decreases with increasing crystallization zone, which is similar to a spring, with an energy storage function that can release internal stress and reduce coating cracking. Interestingly, the amorphous phase still dominates the top zone of the Fe-based amorphous coating without influencing its function.