Effect of aging temperature on microstructure and mechanical properties of (Ti1400+TiC)/Ti6Al4V composites

Titanium matrix composites, due to their high strength, high modulus, and high temperature resistance, have become ideal materials that meet the lightweight and high-performance requirements in the aerospace industry. However, their poor ductility remains a key issue that restricts their widespread application. In this study, (Ti1400+TiC)/TC4 composites were prepared by low-energy ball milling and spark plasma sintering and subjected to solution treatment and aging treatment. The effects of aging temperature on the composition, microstructure, and mechanical properties of the composites were analyzed, and the strengthening mechanism of (Ti1400+TiC)/TC4 composites was discussed. The aging temperature between 350 ℃ and 700 ℃ had little effect on the microstructure of TC4 matrix and the discontinuous three-dimensional network structure of TiC particles. As the aging temperature increased, the elongated α-phase within the Ti1400 region became shorter and thicker, and Cr’s rapid diffusion resulted in β-phase being more widely distributed. After aging at 600 ℃, the tensile strength of the composite was 1202 MPa, and its total elongation reached 11.3 %, showing excellent strength-plasticity matching. The mechanical properties of composites are mainly affected by the microstructure in the Ti1400 region. The elongated α-phase in the Ti1400 region provides high strength for the composite. The thicker α-phase and the widely distributed β-phase led to more uniform strain within the composite, avoiding premature fracture caused by stress concentration near TiC particles and promoting ductility in the composite.