Phase transformation diffusion bonding technology for titanium alloy to stainless steel

The joints of titanium alloy(TA17) and stainless steel(0Cr18Ni9Ti) were obtained by phase transformation diffusion bonding.Effect of parameters on strength of the joint was investigated,and the optimum parameters for bonding are as follows:maximum cyclic temperature is 890℃,minimum cyclic temperature is 800℃,number of cyclic times is 10,bonding pressure is 5 MPa and heating velocity is 30℃/s.Strength of the joint under the optimum condition is 307 MPa,and the time for bonding is 160 s.Scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD) were used to study the fracture appearance of the joint.The study showed that the fracture takes place at somewhere between FeTi and β-Ti layers,and the FeTi layer is the weakest point in the joints.The joint was analyzed by EDS and the ternary phase diagram for Fe-Cr-Ti.The results indicated the presence of σ,Fe₂Ti,FeTi and β-Ti in the reaction zone between stainless steel and titanium alloy.