Effect of interfacial microstructure of TiAl/40Cr diffusion bonding on strength of joint

The interfacial microstructure of diffusion bonding is a critical factor having an effect on the performance of joints, and different interfacial microstructures and reaction phases result in different strengths of joints. The study results on the diffusion bonding of TiAl/40Cr show that when bonding temperature is too high and bonding time is too long, brittle TiC layer and Ti₃Al+FeAl+FeAl₂ layer formed at the interface lead to low tensile strength of joints. When bonding temperature is too low and bonding time is too short, insufficient compact contiguity and elemental diffusion lead to poor tensile strength of joints. Brittle TiC layer arising at the interface leads to poor performance of the joints. Specimen fractures occur mostly on the brittle TiC layer or between the TiC layer and the Ti₃Al+FeAl+FeAl₂ layer.