An experimental investigation on the effects of severely plastic deformation process on the mechanical properties of automotive resistance spot welded aluminum joints

In this paper, the mechanical properties of welded single lap joints of pure aluminum sheets produced by severe plastic deformation (SPD) are considered. SPD in form of a large pre-strain was imposed on aluminum sheets through the constrained groove pressing (CGP) process. Furthermore, CGPed specimens are joined using the resistance spot welding (RSW) method. Welding time and force are maintained evenly. Welding current is raised until ideal failure mode is observed. Finally, mechanical properties of the fusion zone, heat affected zone (HAZ), and base metal of welded SPDed specimens are derived. The results show that by increasing the pre-strain in specimens, an improvement in yield strength, ultimate tensile strength, load carrying capacity, maximum displacement before failure, and nugget diameter is observed. Furthermore, the sensitivity of these parameters to the CGP pass number is considered. Finally, it has been shown that fusion zone and HAZ hardness values can increase by increasing the CGP pass number.