Microstructures and tribological properties of laser cladded Ti-based metallic glass composite coatings

• Ti-based metallic glass composite coatings were prepared by laser cladding.
• The wear resistance is greatly improved by laser cladding of composite coatings.
• Substitution of Ni by Sn increases GFA and wear resistance of the coatings.
• A good balance of crystalline/amorphous phases improves the wear resistance.
• Adhesive wear serves as the dominant wear mechanism of the composite coatings.

Metallic glass composite coatings Ti45Cu41Ni9Zr5 and Ti45Cu41Ni6Zr5Sn3 (at.%) on a Ti-30Nb-5Ta-7Zr (wt.%) (TNTZ) alloy were prepared by laser cladding. The microstructures of the coatings were characterized by means of X-ray diffractometry (XRD), scanning electron microscopy (SEM) equipped with energy dispersive X-ray analyzer (EDXA), and transmission electron microscopy (TEM). Results indicated that the coatings have an amorphous structure embedded with a few nanocrystalline phases and dendrites. A partial substitution of Ni by Sn can improve the glass forming ability of Ti-base metallic glass system, and induce the formation of nano-sized Ni2SnTi phase during the cyclic laser heating. The tribological behavior of both the substrate and the coatings was investigated in detail. A significant improvement in both the hardness and the wear resistance of the coatings was achieved with the addition of Sn. The relationship between the wear resistance and the microstructures of the coatings was discussed.