Low-deformation Dissimilar Welding of Steel to Al Alloy <i>via</i> Solid-state Welding Using Local Resistance Heating

A new solid-state bonding technique using local resistance heating, was employed for dissimilar bonding of 304 stainless steel to 5052 aluminum alloy. The effects of the bonding parameters, including the bonding temperature and time, on joint strength and interfacial microstructure were examined. The joints were successfully produced without macroscopic deformation of base metals within a short time. The joint strength increased with bonding temperature up to 723 K, up to 82 MPa, corresponding to the joint efficiency of 30%, but significantly decreased at 773 K due to the formation of a thick intermetallic compound (IMC) layer. On the other hand, the joint strength increased with bonding time up to 30 s, beyond which it was saturated. Fracture propagated inside the IMC layer and Al near the interface, and through the unbonded interface during tensile tests. The relationship between thickness of the IMC layer and the joint strength showed that a thin IMC layer (< 2 µm) enhanced the joint strength by reducing unbonded interfaces, whereas thicker IMC layer (≥ 2.5 µm) deteriorated the joint strength due to the brittleness of IMC layer. These findings demonstrate that this new bonding technique enables dissimilar metal joining with short processing time and minimal deformation of the base metals.