Abstract: The effect of current density on electrically assisted solid-state bulk joining, so-called electrically assisted pressure joining (EAPJ), of copper (Cu) C11000 and aluminum (Al) 6061-T6 alloys is investigated. During EAPJ, various combinations of electric current density and duration are applied to the cylindrical specimen assembly to reach a fixed peak temperature during continuous axial compressive plastic deformation. Then, an additional electric current is periodically applied to the specimen assembly without plastic deformation to keep the temperature elevated. Microstructural observation confirms that the defect-free joint of the selected material combination is fabricated without melting and solidification. The athermal effect of electric current on the diffusion enhancement can be accommodated by introducing the effective activation energy or the effective temperature. The microstructural analysis also demonstrates that the current density both increases the thickness of the intermetallic compound (IMC) layer at the joint interface and affects the microstructural evolution of joining materials. Finally, the mechanical properties of the joint are strongly affected by the electric current density. The present study provides insight into the effect of electric current density on the solid-state joining mechanism of EAPJ of dissimilar material combinations.

Key words: Solid-state joining, Electrically assisted pressure joining, Copper C11000, Aluminum AA6061-T6, Electroplasticity, Current density