Effects of pulse parameters on in-situ Ti-V carbides size and properties of Fe-based laser cladding layers

The effects of duty cycle and pulse frequency on the carbide size and properties of in-situ TiC-VC reinforced Fe-based cladding layers were studied. Heat input increased and carbide particle sizes decreased with increasing numbers of duty cycles. As the pulse frequency increased from 5 Hz to 5000 Hz, carbide particle sizes first increased and then decreased. Carbide refinement was mainly induced by a rapid cooling rate at low pulse frequencies, and high-speed Marangoni flow in the molten pool at high pulse frequencies. The hardness and corrosion resistance of cladding layers varied inversely with carbide particle size. The 5 Hz cladding layer had the highest hardness and best corrosion resistance, while the 500 Hz layer showed poor properties because of carbide agglomeration.