Synergistic effects of a bionic villi structure and multiple hydrogen bonds on the increase in interfacial bonding strength of a 30-wt.% GF/PET-2024 aluminum alloy

In recent years, metal‒thermoplastic polymer hybrid joints have been widely used in lightweight advanced aircraft and new energy vehicles. In this work, the method of machine milling + FeCl₃ corrosion + coating KH-892 was used to construct a viscous bionic villi structure on the surface of A2024 aluminum alloy, which greatly improved the interfacial bonding strength of a 30-wt.% glass fiber-reinforced PET-A2024 aluminum alloy joint (expressed as 30-wt.% GF/PET-A2024 joint). The synergistic action of the millimeter column produced by milling and the micron-scale porous structure produced by corrosion results in multiscale mechanical interlocking and increases the interfacial bonding strength of 30-wt.% GF/PET-A2024 to 44.2 MPa, which is 13.7 times greater than that of untreated joint. FTIR results show that the KH-892 coating can change the viscosity of the villi surface, which makes it easier for the bionic villi surface to bond with PET. Under the action of millimeter‒micron multiscale mechanical interlocking and multiple hydrogen bonds, the interfacial bonding strength of 30-wt.% GF/PET-A2024 increases to 54.8 MPa.