The high temperature deformation behavior of hot rolled annealed TC4 titanium alloy profiles was investigated by uniaxial tensile test.The effects of deformation temperature and strain rate on the mechanical properties of TC4 titanium alloy and tensile fracture behavior were analyzed.The results show that the tensile strength is decreased with the increase of temperature at the same tensile rate in range of 0.236～1 mm/min.When the deformation temperature is fixed at 773、993 and 1 093 K

the tensile strength of the alloy is less affected by the tensile rate

and the tensile strength remains basically unchanged.With the deformation temperature of 1 093 K

the tensile strengths increased with the increase of the stretching rate.With the increase of deformation temperature or the decrease of tensile rate

the number of dimples in the fracture is increased

and the shape of the dimple gradually becomes regular.The fracture mode of the specimen is transformed by the mixed fracture of brittle fracture and ductile fracture.It is a ductile polymerized ductile fracture and finally becomes ductile fracture.