Microstructure and mechanical properties of TC4 composites reinforced with multiscale TiCp

Titanium matrix composites (TMCs) face a trade-off between strength and toughness. Here, TC4 alloy and TMCs with 5, 10, and 15 wt% multiscale TiC particles (TiCₚ) were fabricated by hot pressing. The effect of TiC content on microstructure and mechanical properties was investigated. TC4 shows a coarse basket-weave structure. Adding TiCₚ refines the microstructure. TiCₚ (submicron to 50 μm) distribute along grain boundaries, evolving from dispersed to semi-continuous and finally to a continuous network with coarse-particle skeleton as TiC content increases. Porosity, hardness and strength increase with TiC content, while elongation first increases then decreases, peaking at 5 wt% TiC. Dynamic impact tests show that TC4 has the lowest maximum stress and relatively large maximum strain. Higher TiC content increases maximum stress but reduces maximum strain for 10% and 15%TiC/TC4, leading to insufficient energy absorption and fragmentation. Benefiting from high density, grain refinement, dispersion strengthening and multiscale reinforcement, 5%TiC/TC4 achieves the highest stiffness together with high hardness, strength and toughness, exhibiting the best energy absorption and structural integrity under dynamic impact. This study provides an experimental basis for designing high-strength, high-toughness TMCs.