Solid state diffusion bonding of Inconel 718

Abstract

Solid state diffusion bonding of Inconel 718 has been studied. Mechanical tests and metallographic examinations were used to evaluate the joint quality. The effect of bonding time, temperature, and pressure on the joint integrity was assessed. The results showed thatpartial recrystallisation occurs in joints bonded attemperatures lower than 970°C. In addition, large amounts of δ phase precipitates were also found and both the ductility and the tensile strength were poor. Nevertheless, the joint strength was comparable to thatof the parent metal when bonding was carried outat temperatures greater than 970°C. When bondingwas carried out at 1000°C, a pressure of 32 MPa, and a bonding time of 30 min, the joint tensile strength obtained was 874 MPa. There was no further improvement with increasing bonding time beyond 240 min.