Enhanced properties of titanium matrix composites via in-situ synthesized TiCx and Ti5Si3 with network structure

Abstract

In-situ network-structured (TiCx + Ti5Si3)/TC4 composites were fabricated via a low-energy ball mill and hot-pressing sintering based on the reaction between Ti3SiC2 and Ti. The microstructure evolution, mechanical properties, and tribological behavior of the composites with different amounts of Ti3SiC2 were studied. The experimental results show that the microstructure of the matrix transforms into the equiaxed structure with the addition of Ti3SiC2. The in-situ TiCx particles are mainly distributed around the matrix and form a network structure, as the Ti3SiC2 content is 5 vol%. Compared with neat TC4, the hardness, tensile strength, and wear resistance of the composites can be significantly enhanced. Moreover, the composite with 5 vol% Ti3SiC2 displays excellent comprehensive properties. The tensile strength of the composite is 1165 MPa, increased by 34.7 % over the neat TC4 and its elongation reaches 8.5 %. Meanwhile, the wear rate of the composite decreases to 24.5 × 10−5 mm3/(N·m), which is reduced by 16.7 % compared with the neat TC4. It is worth noting that the aggregation of particles can seriously reduce the mechanical properties of the composites.