Diffusion bonding of TiAl to Ni-based superalloy

Diffusion bonding of TiAl to Ni-based alloy using Ti interlayer was studied.The microstructure of the joint and effect of bonding temperature on microstructure and properties of the joint were investigated,and the mechanism of the formation of reaction layers was also discussed.The experiment results show that the interfacial structure of the GH99/Ti/TiAl joint is GH99/(Ni,Cr)_ss/rich Ti-(Ni,Cr)_ss/TiNi/Ti₂Ni/α-Ti+Ti₂Ni/Ti(Al)_ss/TiAl+Ti₃Al/TiAl.With the bonding temperature increasing,the thickness of reaction layers increases.The shear strength of the joint increases with the bonding temperature,and goes through a maximum at 1173 K/30 min/20 MPa and thereafter falls off.The maximum shear strength is 260.7 MPa.