Melting behavior and tribological properties of titanium-based laser cladding layer WC on the surface of TC4

Abstract

WC is one of the cladding synthetic materials that effectively improve the surface tribological properties of TC4 alloy, but it is easy to produce residues in the coating, which always plagues the quality and performance of the coating. In this study, TC4+WC titanium wear-resistant coatings with different WC addition ratios (5%, 10% and 15% (mass fraction /%)) were prepared on the surface of TC4 by coaxial powder feeding laser cladding technology, and the macrostructure, microhardness and tribological properties of the coating were analyzed and studied, focusing on the melting and residue mechanism of WC in the molten pool. The results show that the addition of WC does not affect the types of phases formed in the coatings. The precipitated phases mainly include in-situ TiC and matrix phases α-Ti and β-Ti. Among them, TiC and the remaining WC particles in the coating form a coherent package mosaic structure phase. The decomposition of WC in the molten pool is prevented, leading to the remaining WC is prone to residue and agglomeration. The amount of WC added is positively correlated with the microhardness of the coating. As the WC content in the material system gradually increases, the wear resistance of the coating gradually increases, and compared with the TC4 substrate, the wear rate of the coating decreases by about 21.1%, 38.2%, and 56.1%, respectively, but the residual WC leads to local stress concentration in the friction and wear process of the coating, the tribological performance fluctuates significantly.

Keywords

• tc4
• laser cladding
• wc
• melting behavior
• tribology