A study on the influence of laser power on microstructural evolution and tribological functionality of metallic coatings deposited on Ti-6Al-4V alloy

摘要

Metallic Ti-Co binary coatings were fabricated on titanium alloy (Ti-6Al-4V) substrate by laser surface cladding technique using a continuous wave RofinSinar 4 kW Nd:YAG laser. The influence of laser power on microstructure, hardness and tribological performance of Ti-Co laser clad coatings on titanium alloy (Ti-6Al-4V) was examined. Laser powers of 750 and 900 W were varied with constant scan speed of 1.2 m/min. A beam size of 3 mm and argon shield gas flow rate of 1.2 L/min were set as the operating laser parameters. Phase identification and morphological studies of the coatings were carried out using X-ray diffractometry (XRD) and scanning electron microscopy (SEM), respectively. Based on the results of laser process optimisation, it was observed that both laser powers produced clad coatings with good metallurgical bond with no cracks or pores in the coatings. With respect to the substrate (Ti-6Al-4V), the microstructure, hardness and friction/wear behaviour of Ti-Co coatings on Ti-6Al-4V substrate were enhanced obviously.