Improved Interfacial Bonding Strength of Hot-Pressed Aluminum Alloy/GFRTP Joint via a Hybrid Surface Pretreatment

Achieving stable joining of metal to glass fiber reinforced thermoplastic composite (GFRTP) is crucial for reducing structural weight and conserving energy. This study adopted a hybrid surface treatment, including laser texturing followed by silane coupling, on aluminum alloy (6061Al) to enhance bonding strength with GFRTP via hot-pressing joining. The results indicated that the wettability of molten GFRTP on the aluminum alloy surface was improved and the physical interlocking between the two materials was enhanced after laser texturing, resulting in a tight bonding interface. After silane coupling treatment, the new chemical bonds were detected at the interface, which proved the silane coupling film promoted the interfacial chemical interaction and improved the joint reliability. Due to improved mechanical interlocking and chemical bonding, the tensile-shear strength of the joint increased to a maximum of 11.55 MPa, which was increased by 7.1 times compared to the pretreated condition. These results suggested the future process optimization could enhance the stability of metal–GFRTP hybrid structures.