Cracking control technology of TiC/Ni coatings prepared by in-situ fabrication through laser cladding

There are many cracks in TiC/Ni coatings prepared by in-situ fabrication through laser cladding.The reasons for crack initiation in the coatings were analyzed from the microstructure, the phase composition, the residual stress, the macro morphology and the fracture observation.Corresponding cracking control measures were also proposed.The investigation indicated that the cracks of the TiC/Ni coatings are mainly brittle cold cracks caused by hard brittle phases and internal residual stress.The replacement reaction(M₂₃C₆+Ti→M+TiC) occurs by increasing the content of Ti powder.Therefore, cracks of the coatings can be reduced or eliminated.Moreover, intriguing microstructures of the coatings are obtained with enhanced plasticity and toughness and reduced residual stress by nickel powder addtion or by optimizing processing parameters, thus the cracking susceptibility can be decreased.