Dissimilar joining of polymer to metal via additive porous layer fabricated by cold spray deposition technique

Dissimilar joining of polymers to metals is essential for achieving weight reduction and enhancing collision safety in automotive structures. However, establishing a polymer/metal joining remains challenging owing to the significant differences in their chemical and physical properties. In this study, a porous layer was additively fabricated on aluminum alloy 5052 (AA5052) by the cold spray (CS) deposition technique to facilitate the direct joining of polyether ether ketone (PEEK) to AA5052 through friction stir welding (FSW). The feasibility of using a porous CS layer for FSW of polymers to metals and the effect of the porous structure on the strength of joints were examined. During FSW, the PEEK penetrated the porous CS layer, improving mechanical interlocking. Lap shear testing demonstrated that increased porosity within the CS layer increased fracture loads. These findings indicate that the added porous CS layers improve joint strength by enhancing mechanical interlocking. This study highlights the potential of additive porous CS layers as a practical solution for dissimilar polymer/metal joint assembly.