Effect of laser power on the performance of in situ TiC enhanced Al-based composite coatings

To enhance the surface wear resistance of 2Cr12MoV steel and improve its service life, TiC/Al composite coating was fabricated on the surface of 2Cr12MoV steel using the CO2 laser cladding system. The effect of laser power on the coating was investigated. The microstructure, hardness, phase composition, and wear resistance of the cladding layer under different laser powers were studied. The results showed that the phase composition of the composite coating consisted of an Fe0.75Al0.25 metal compound, a Ti-Cr solid solution, TiC, and an Fe-Cr solid solution. As the laser power increases, the average hardness of the composite coating was approximately 1.6–1.7 times than the substrate, but excessive power would lead to a decrease in coating hardness, which was due to the substrate dilution effect and grain coarsening. Moreover, the wear resistance of the coating was also improved. The wear rate of the coating under a power of 1400 W was the lowest [7.47 × 10−6 mm3/(N m)]. The wear mechanism of the coating mainly included fatigue wear, oxidation wear, and abrasive wear.