Abstract: Titanium matrix composites reinforced with different mole ratios between TiB and TiC were fabricated by common casting technique utilizing the self-propagation high-temperature synthesis reactions between titanium and B₄ C and graphite. The mechanical properties of the titanium matrix composites at high temperature were tested. The results show that tensile properties of the titanium matrix composites at high temperature are improved obviously due to the in situ synthesized reinforcements. Fracture mechanism is related to temperature. When the temperature is low, the fracture of reinforcement makes the composite failure. As temperature increases, the debonding between matrix alloy and reinforcement TiB conduces to the composites failure. Because the crack is likely to nucleate and grow on the end of TiB whiskers which makes the composites to failure, the addition of graphite forms more TiC particles and improve the mechanical properties of titanium matrix composites at high temperature.