Abstract Scope |
A novel cored wire made of Ni metallic sheath and WC powders was developed for laser deposition of hybrid carbides reinforced Ni-Ti matrix composite coatings, to enhance the tribological performance of TC4 alloys. Under the irrigation of the high-energy laser beam, the in-situ reactions between the Ti substrate and the Ni-WC cored wire were triggered, forming the matrix of Ni-Ti intermetallics and the reinforcements of TiC, WC, and W2C carbides in the coatings. As the wire was delivered by front feeding, two typical wire transfer modes including slag column transfer and wire stubbing transfer were observed under various processing parameters. The formed slag column could decrease the powders splash, and facilitate the homogenization of the in-situ synthesized carbides in the matrix. Consequently, the coating produced by slag column transfer possessed the maximum hardness and the ideal wear resistance, which were 2 and 23 times higher than the substrate, respectively. This study proposes a high-efficiency method for additive manufacturing homogenous ceramics-reinforced metal matrix composites (MMCs) layers; the uniform distribution of reinforcements in a matrix can be achieved through precisely controlling the transfer behavior of cored wire, which provides a promising way for surface modification of Ti alloys. |