Study on the impact of laser power variation on the performance of Ti-6Al-4 V coating by laser cladding on HT250

To enhance the wear resistance of the HT250 surface and eliminate ledeburite formation at the coating-substrate interface, a dual-layer Ti-6Al-4 V coating was created on HT250 surfaces through laser cladding. The influence of varying laser power on the microstructure, hardness, and wear resistance was investigated. The results indicate that a laser power of 600 W for the second layer can eliminate the formation of ledeburite at the coating-substrate interface, fabricating a crack-free cladding layer with a maximum hardness of 480.9 HV. Needle-like TiC was in-situ synthesized in the surface zone when the laser power was set at 600 W and 800 W. The surface hardness at 600 W is 1.1 and 1.4 times higher than that at 800 W and 1000 W, respectively. The optimal wear resistance was achieved at a laser power of 600 W, exhibiting 0.52 and 0.40 times the wear rates compared to those at 800 W and 1000 W, respectively, at 500 °C. At temperatures below 300 °C, the predominant wear mechanisms for all three coatings were abrasive wear and a small amount of oxidative wear. As the temperature increased to 500 °C, oxidative wear became the primary wear mechanism for the coatings.