Pulsed electric current bonding between Ni-based single crystal and powder metallurgy superalloys

• PECB was first used between Ni-based single crystal and powder metallurgy superalloys.
• Temperature field during PECB process was obtained by ANSYS simulation.
• Microstructure variation and element diffusion was studied in PECB interface.
• Non-uniform distribution of temperature and microstructure occurred in PECB interface.
• PECB under 1100 °C/35 MPa/10 min was favorable for better tensile strength.

Pulsed electric current bonding (PECB) between Ni-based single crystal (SC) and powder metallurgy (PM) superalloys was first carried out to investigate the influence of PECB conditions on the interface microstructure and element diffusion. ANSYS simulation was employed to obtain temperature distribution during PECB process. Non-uniformity of temperature gradient occurred in the bonding interface, leading to non-uniform interface microstructure. Irregular γ′ precipitates developed in DD6 diffusion zone, and uniform spherical γ′ precipitates reprecipitated in FGH96 diffusion zone. Interface microstructure under 1100 °C/35 MPa/10 min was more desirable due to few large irregular γ′ precipitates formed. Average tensile strength at 750 °C was evaluated to be 978 MPa for PECB joints with the highest tensile strength of 1010 MPa under 1100 °C/35 MPa/10 min.