Effect of Laser Power on Cracking Behavior of TiC/Fe-based Cladding Coatings

TiC/Fe-based cladding coatings were successfully prepared by high-speed laser cladding technology through the modulation of laser power. The macroscopic and microscopic structures of the coatings were analyzed by nondestructive testing, optical microscopy (OM) and scanning electron microscopy (SEM). The temperature and stress fields of the coatings were also analyzed by finite element simulation. The results showed that the crack sensitivity of the cladding coatings decreased with the increase of laser power. When the laser power was elevated from 2.4 kW to 3.6 kW, the maximum temperature of the molten pool rose from 3,162 K to 4,203 K, and the temperature gradient enhannced as well. Although the residual stress of the coating increased with the increase of laser power, the higher laser power slowed down the cooling rate of the melt pool, which would promote the growth of TiC ceramic particles and make them uniformly distributed in the melt pool, and thus reduce the crack sensitivity.