LAUSR

This study suggested the judicious application of the resin pre‐coating (RPC) technique during adhesive bonding. Electrochemical surface treatment (ECST) and ultrasonic chemical treatment (UCT) were done on the Al 7075 alloy. Subsequently heterogeneous adhesive bonding of the ECST‐processed and the UCT‐processed alloy with three different CFRPs, namely unidirectional (UD) CFRP, 4‐Harness Satin‐weaved (4HSW) CFRP, and plain‐weaved (PW) CFRP was investigated. ECST and UCT processes resulted in trench‐type surface structures and cavitation pits, respectively. After ECST, contact angles of deionized water and diiodomethane reduced drastically. The highest strengths for the adhesive joints with UD, 4HSW, and PW CFRPs were 28.50, 30.40, and 26.85 MPa, achieved respectively after 10 V ECST without RPC, 1 M UCT without RPC and 1 M UCT with RPC technique. Thin layer cohesive failure at the alloy interface (TLCF‐AI) respectively increased and decreased after application of the RPC technique on the ECST‐processed and the UCT‐processed alloy surface. RPC technique after ECST decreased the single lap shear strengths, whereas this after UCT increased the single lap shear strengths of the heterogeneous adhesive joints with all considered CFRPs. The effectiveness of the RPC technique depended on the combinations of adherend surface morphologies and adhesive properties.