Effect of bonding temperature on interfacial microstructure and properties of TiAl/Ti_3AlC_2 joint

Diffusion bonding of TiAl alloy and Ti₃AlC₂ ceramic was achieved by using Ti/Ni composite interlay. The interfacial microstructure of TiAl/Ti₃AlC₂ joint was analyzed by SEM, EDS and XRD, and was determined as TiAl/Ti₃Al+Al₃NiTi₂/Ti₃Al/α-Ti+Ti₂Ni/Ti₂Ni/TiNi/Ni₃Ti/Ni/Ni₃(Ti, Al)/Ni₃Al+TiC_x+Ti₃AlC₂/Ti₃AlC₂. As the bonding temperature increased, the thickness of Ti_ss in TiAl/Ti interface gradually reduced, the Ti₃Al intermetallic layer gradually thickened, and the thickness of TiNi intermetallic layer increased significantly, while the thickness of Ti₂Ni and Ni₃Ti intermetallics layers remained substantially constant. The shear strength of joints first increased and then decreased with increasing the bonding temperature. The maximum shear strength of the joint can reach 85.3 MPa when bonded at 850℃. The joint fracture occurred mainly in Ni/Ti₃AlC₂ interface and Ti₃AlC₂ matrix.