Microstructure and wear resistance of TiN-NiCrBSi laser clad layer on titanium alloy surface

Ni based clad layer reinforced with TiN particles was prepared on the surface of TC4 alloy adpting laser cladding process, using the mixed powder of TiN powder and NiCrBSi powder as starting material. The microstructure of the laser clad layer was characterized by XRD, SEM and TEM. The microhardness and wear resistance of the laser clad layer were examined. The results show that the laser clad layer is divided into two zones: the clad and dilution zones. In the clad zone, TiN particles and M23C6 are distributed in matrix of the γ-Ni dendrites and the eutectics consisting of γ-Ni and Ni3B, and the microhardness is 9000 MPa-12000 MPa. The dilution zone is a mixture of Ti-6Al-4V alloy and Ni-base alloy, and presents a microstructure of dendrites and cells. The clad layer is reinforced by particles, solution, and grain-refining, resulting in a remarkable increase in wear resistance comparing with Ti-6A1-4V alloy.