Microstructure and properties of diffusion bonded interface of titanium-copper interlayer-carbon steel composite tube

The composite tube of titanium/steel was prepared by the drawing and inner pressure diffusion technique by using Cu foil as an interlayer. The interface microstructure,fractured surface and components were investigated with OM,SEM, XRD and EDS. The bonding strength of the interface was studied by shear test. The results show that the metallurgical bonding of titanium and steel was obtained by the drawing and inner pressure diffusion technique with copper foil as an interlayer. The interface components analysis show that the elements diffusion was found between the titanium/copper interface and the diffusion layer was formed. The thickness of the diffusion layer increased with increasing of diffusing time. The Fe-Ti brittle compound was prevented by using copper interlayer at lower diffusion temperature. The shear strength of titanium/steel interface firstly increased and then decreased with diffusion temperature increasing. Copper interlayer can improve the shear strength significantly, and the maximum shear strength can reach 310 MPa.