High addition content WC particle reinforced titanium matrix composites fabricated by concurrent wire powder feeding laser directed energy deposition

Abstract

Concurrent wire powder feeding laser directed energy deposition (L-DED-WP) combines the advantages of both powder feeding and wire feeding laser deposition. This technique offers distinct advantages in producing composites with high addition content. A key challenge in composite fabrication methods is achieving high addition content without compromising quality or mechanical properties. This work addresses this gap by fabricating WC/Ti6Al4V composites with varying WC additions (40 wt%, 60 wt%, and 80 wt%) and analyzing their microstructure and mechanical properties. The mechanical properties of composites are influenced by the matrix, reinforcing phase, and the reaction layer. The study examines the evolution of phase composition, including W₂C, WC, W, TiC, and [W, Ti]C_1-X, and the effect of WC content on microstructures and tribological properties. The results show that TiC precipitation increases with higher WC content, with TiC morphology transitioning from chain eutectic to equiaxed and dendritic primary TiC. The reaction layer thickness increases from 4.12 μm to 11.76 μm as WC content increases. Increased precipitation of TiC and [W, Ti]C_1-X facilitates the heterogeneous nucleation of β(Ti, W). The matrix’s β(Ti, W) is refined, reducing the texture strength. During the wear process, the un-melted WC (UMWC) particles share part of the frictional force, thereby preventing severe wear of the matrix. The composites exhibit significant improvements in tribological performance compared to Ti6Al4V, with a 53.19 % reduction in the friction coefficient and a 94.55 % decrease in wear mass loss for the 80WC/Ti6Al4V composite. This research demonstrates the potential of L-DED-WP for fabricating high performance composites with high WC content, offering a cost effective and efficient approach for aerospace applications.