Effect of laser power on microstructure and properties of Ti-Al/WC composite coatings

Abstract

To enhance the performance of TC4 titanium alloy, laser cladding technology was used to prepare a Ti-Al/WC composite coating on its surface, and the influence of laser power on the physical phase composition, microstructure, friction and wear properties and hardness of the coating were studied. The studies indicate that the coating consists of Ti3Al2, TiAl, Ti3Al gray matrix organization and TiAl, Ti2AlC gray-white precipitation organization. When laser power increases, the gray-white precipitated tissue increases significantly, and the precipitated TiC changes from dot-like, flake-like, and short rod-like to dendritic. When the laser power is 1200W, TiC gradually transforms into Ti2AlC phase, and the shape of the precipitated tissue becomes irregular. In comparison to the substrate, the average hardness of the coatings rises by 1.88-2.27 times, and the maximum average hardness of 635.6HV is achieved at 1000W of laser power. The cladding layer has better wear resistance at laser powers of 1000W and 1200W. The wear mechanisms of the coatings are abrasive and adhesive wear.