The static and dynamic fracture toughness, strength, and ductility of various titanium alloys were investigated. The crack propagation toughness and fatigue crack propagation rate under both static and dynamic conditions were also investigated an compared with that of T-6Al-4V at the elevated temperatures. The results showed that sudden decrease in strength, fracture toughness values or the stress intensity factors were noticeable at the elevated temperature of 1123K. The fracture toughness values evaluated from the load values (stress intensity factors) also decreased at a single annealing temperature of 1123K. The sudden decrease in strength was recovered by conducting duplex annealing. By duplex annealing, Widinanstatten alpha precipates in beta and then beta was able to stabilize the strength.