MICROSTRUCTURE EVOLUTION AND WEAR RESISTANCE OF LASER CLADDING NI-BASED COMPOSITE COATINGS AFTER PULSED LASER

Researchers have improved the wear resistance of coatings by adding hard phases or heat treatment to extend the service life of molds. However, the above methods increase the production cost and prolong the production cycle time, which weakens the advantages of laser cladding technology. In this paper, we first explore the effect of pulsed lasers on coating properties by adjusting the pulse frequency. It is found that the microstructure of the laser cladding Ni-based composite coating is refined and the microhardness is significantly improved in the range of pulse frequency from 2 to 100[Formula: see text]Hz. By further adjusting the duty cycle, we found that more NbC phases precipitated at the grain boundaries and distributed more uniformly when the duty cycle was 50%. The microhardness reaches 729.7[Formula: see text]HV[Formula: see text]. Compared with the coating prepared by continuous wave laser, the microhardness is increased by 22.1%, and its wear resistance is improved by 65.6%. This investigation can provide a useful reference for the application of laser cladding technology.