Mechanical Property Enhancement Mechanism of W/TC4 Composites by Laser‐Directed Energy Deposition

Titanium‐based composites represent one of the key development directions for new materials in aerospace applications. In this article W/TC4 composites with high W addition (wt%) were prepared by laser‐directed energy deposition technology. The melting of W particles and the precipitation process of W dendrites were revealed. The mechanism of W addition on microstructure refinement and mechanical properties improvement of composites was described. The results indicate that W particles form a strong metallurgical bond with the Ti alloy matrix, and dendritic or granular substitution solid solutions composed of W and Ti have appeared within the Ti alloy matrix. The addition of W exhibits a pronounced effect on grain refinement. In composite specimens containing 70 wt% W, the average grain size of β‐Ti reached 14.34 μm, which is over 40% smaller than that observed in specimens with 50 wt% W. Furthermore, the anisotropy of the composite material significantly decreased with increasing W content. As the W content increases, the microhardness of the composite material gradually rises. Among them, the microhardness of the W 70 wt% specimen reached 472.9 ± 29.7 HV _0.2 . The increase in microhardness is primarily attributed to the load‐bearing strengthening effect of unmelted W particles and the solid solution strengthening effect of the W element. Furthermore, friction and wear tests indicate that both the arithmetic average height and mean square height of the wear surface gradually increase with the rising proportion of W addition.