Densification kinetics, microstructural evolution, and mechanical properties of (TiB+TiC+Ti3Si)/TC4 composites under pressureless sintering

Abstract

The pressureless sintering (PLS) technique holds substantial potential in manufacturing cost-effective composites with intricate shapes. Nonetheless, it can lead to reduced density in titanium matrix composites (TMCs), affecting their mechanical properties. This study introduces a novel approach to producing high-density TMCs utilizing polymer encapsulation on hydride-dehydride (HDH) TC4 particles through wet mixing. The coexistence of the sintering Si-B-Ti/Al-C-N liquid phases and a dual approach to deoxidizing HDH TC4 particles synergistically enhance the compactness of the TMCs, achieving densities as high as 98.5% during PLS. The densification mechanisms for (TiB+TiC+Ti₃Si)/TC4 composites under different conditions kinetics were revealed by calculating the effective grain growth exponent and activation energy. The (TiB+TiC+Ti₃Si)/TC4 composite, produced through PLS at 1300 ℃ for 1.5 hours, exhibits exceptional properties with a compressive strength of 2087 MPa and a fracture strain of 41.7%. This research will provide a feasible avenue for developing high-performance TMCs using the polymer as the reinforcement source and low-cost HDH TC4 powder during PLS.