Effect of intermetallic compound layer size on Al/steel spot weld properties

Abstract Joining aluminum to steel presents challenges due to their distinct physical and metallurgical properties. Resistance spot welding is a used technique for producing Al/steel joints. Fusion between the two metals cannot occur, proper process parameters enable the formation of an intermetallic compound at the interface. While its thickness and composition are known to influence joint performance, its diameter can also be crucial. In this study, DP600 steel was joined with two aluminum alloys - 5754-H22 and 6082-T6. The effects of welding time and current on the intermetallic compound thickness and diameter were examined, along with tensile-shear and cross-tensile tests. Results indicate that increasing compound diameter enhances joint strength, primarily controlled by welding time.