Microstructure and wear resistance of in-situ TiC reinforced Ti-based coating by laser cladding on TA15 titanium alloy surface

Abstract

The TiC-reinforced Ti-based coating was prepared in-situ on the surface of the titanium alloy TA15 by laser cladding technology. The forming quality, microstructure, phase composition, hardness, and tribological properties were investigated by optical microscope, X-ray diffractometer, scanning electron microscope, energy spectrum analyzer, microhardness tester and friction and wear apparatus. The results show that the coating mainly composes of β-Ti, Co3Ti, CrTi4 and TiC, and the good metallurgical bond is formed between coating and the substrate. The microstructure of the coating bond zone is planar crystal and columnar crystal, the middle is dendritic, and the top is equiaxed. Significant differences in the morphology of TiC are observed in each micro-area of the coating. TiC of the top and middle areas is thick dendritic and petal-like, while TiC of the bonding area is needle-like and spherical. The maximum microhardness of the coating is 715HV, which is about 2.1 times than that of TA15 (330HV). Under the same conditions, the wear loss of coating is 30.14 mg, which is about 30.7% of TA15(98.11 mg). The wear mechanism of the cladding coating and substrate is a composite wear mode of adhesive wear and abrasive wear, but the wear degree of the coating is lighter.

Keywords

• ta15
• laser cladding
• ti-based coating
• microstructure
• wear resistance