Formation of the joint during solid-state bonding of Ni-based superalloys EP975 and EK79


The effect of pressure welding involving a shear strain along the contact surface on the formation of a solid-state joint of dispersion-strengthened Ni-based superalloys EK79 and EP975 is studied. Quality of the joints is assessed in terms of porosity and tensile strength tests. It is shown that a 20 µm width transition diffusion zone is formed in the solid-state joint area during the pressure welding process. EDX analysis revealed the occurrence of cross diffusion processes of alloying elements W, Al, Cr in the diffusion zone. According to the tensile tests at room temperature, it is found that the solid-state joint strength is about 0.49-0.62 of the EK79 alloy strength level.