Study on laser cladding of NiCrBSi (Ti)-TiC metal-ceramiccomposite coatings on titanium alloy

NiCrBSi-TiC and Ti-TiC metal-ceramic composite coatings have been respectively cladded on the surface of TC4 alloys by laser.The microstructure and microhardness of coating has been analyzed.The results show that the NiCrBSi-TiC coating is consisted of γ-Ni primary dendrites,γ-Ni and Ni3B,M23(CB)6,CrB eutectics and TiC particles uniformly distributing in the substrate. Partial dissolution or melting appearing on the edges of TiC particles in the cladding process is observed. While in the Ti-TiC coating,total dissolution melting of TiC particles and their regrowth in the form of dendrites during cooling are found. The microhardness of NiCrBSi-TiC coating (HV900～1200) is distinctly higher than that of Ti-TiC coating (HV600～700).