Effect of TiC Content on Microstructures and Properties of Laser Cladding TiC/Ti Based Composite Coatings

Abstract

To improve the corrosion resistance and load-bearing performance of titanium alloy, the TiC/Ti based composite coating with good metallurgical quality was prepared on the surface of TC4 titanium alloy by using Diode laser, and the effect of TiC content on the microstructures and properties of TiC/TC4 cladding was studied. The microstructure and phase constitution of the coating were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD), the micro-hardness, corrosion resistance and the load-bearing performance of the coatings were evaluated. The results show that the cladding consists of TiC, TiC0.95, NiTi2 and α'-Ti, and the overall hardness of the coating fluctuates greatly. The micro-hardness in hard phases and in the heat affected zone are 1000-1500HV and about 437HV respectively. While the mass fraction of Ni coated TiC is not higher than 60%, higher corrosion resistance of claddings can be obtained with the increase of the mass fraction of Ni coated TiC, reaching a maximum at 60%; while the mass fraction of Ni coated TiC is not higher than 50%, the load-bearing capacity of claddings can be improved with the increase of the mass fraction of TiC, reaching a maximum at 50%.

Keywords

• laser cladding
• TiC coating
• microstructure
• corrosion resistance
• load-bearing capacity