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Vacuum brazing of TiAl alloy and 316L stainless steel (SS) was conducted using Zr-42.9Cu-21.4Ni amorphous filler metal. The effect of brazing temperature and brazing time on the microstructure and shear properties of the dissimilar metal joints between TiAl alloy and 316L stainless steel was investigated. The results show that the interface of the brazed joint can be divided into six different reaction layers. The microstructure of the brazed joints from TiAl alloy to 316L stainless steel at 1040 ℃/10 min is γ(TiAl)+AlCuTi/α2(Ti3Al)+AlCuTi/AlCu+ZrCuNi+FeZr/Cu8Zr3+ZrCuNi+TiFe+Fe2Zr/FeZr+Fe2Zr+TiFe2+ZrCu/α-(Fe, Cr). With the increase of brazing temperature, the shear strength of brazed joints increase first and then decrease. The maximum shear strength of 162 MPa is obtained at 1040 ℃/25 min. Fracture analysis indicates that cracks initiate at the interface of FeZr+Fe2Zr+TiFe2+ZrCu, and then propagate along Cu8Zr3+ZrCuNi+TiFe+Fe2Zr and α-(Fe, Cr) with cleavage fracture pattern.

The interfacial microstructure evolution, growth kinetics of the intermetallic compound (IMC) and mechanical properties of Fe/Al dissimilar metal joints were investigated by vacuum diffusion bonding. The results show that there is no IMC formed on the interface of the joint bonded at temperature of 550 ℃. When the bonding temperature exceeds 575 ℃, the interfacial region is composed of Fe2Al5 and a small amount of FeAl3, and the thickness of IMC layer increases rapidly with the increase of bonding temperature.Under the bonding time of 120 min, the shear strength of the joint increases first and then decreases with the increase of the bonding temperature, and the shear strength of the joint reaches the maximum value of 37 MPa.According to thermodynamic theory, the Gibbs free energy change of Fe2Al5 is the lowest in the range from 550 ℃ to 625 ℃, and then followed by that of FeAl3, and the generated sequence of interfacial IMC can be: Fe2Al5→FeAl3. The interfacial IMC grow in a parabolic manner as a function of bonding temperature, and its growth activation energy is 282.6 kJ·mol-1.The growth rates of IMC at the interface are 1.13× 10-14, 3.59×10-14, 1.21×10-13 m2·s-1 at 575, 600, 625 ℃ respectively.