The diffusion bonding of TC4 titanium alloy plate was conducted under the condition of 910℃ temperature and 3.4MPa pressure. Specimens were cut from the gained joints to conduct metallographic analysis. It indicated that the sound joints can be achieved under selected process parameters

since several microscopic defect only existed within the depth of 1mm from the surface of the joints. Subsequently

the mechanical properties of diffusion bonded joints were studied. The static tensile test

fracture toughness test and nano indentation test were carried out for diffusion bonded joints. The results show that the yield strength of the gained diffusion bonded joints is 887MPa

its tensile strength is 948MPa and fracture toughness is 101.9MPa·m1/2，presenting little difference of properties with raw materials. The results of nano indentation tests indicate that the micro elastic modulus of the bond line and the based metal region are 180.2GPa and 178.0GPa respectively.