Abstract: Direct plastic/metal molding technology is one of the research focuses in the vehicle lightweight technology currently. The micro-nano needle-like structure is prepared on the surface of aluminum alloy via chemical etching and anodization techniques, and the direct plastic/metal compound molding is successfully realized by a self-developed ultrasonic-assisted hot pressing technology. The influence of ultrasonic parameters on the interface structure and bonding properties of polypropylene/aluminum alloy hybrid is investigated. The interfacial morphology of the hybrid is displayed by using ultra-thin section technology and reverse dissolving method. The results show that the interfacial tension-shear strength of the non-ultrasonic pressing molded sample was 12.04 MPa, the average thickness of interfacial layer is 6.47 μm, and the tensile- shear failure is mainly presented as the mixed failure mode. As for the ultrasonic-assisted hot-pressed hybrid, the tensile-shear strength reaches 19.90 MPa, which is increased by 65.3% against the non-ultrasonic hot-pressed sample, and the average thickness of interfacial layer decreases to 5.40 μm. Moreover, a good micro-mechanical interlocking structure is formed on the interface surface of the ultrasonic-assisted hot-pressed hybrid, and the failure mode is mainly cohesive. It can be concluded in the experimental that ultrasonic helps plastic melt to enter the micro-nano structures on the metal surface and form micro-anchoring structures, which successfully realizes the direct plastic/metal integrated molding.

Key words: polymer/metal hybrid, ultrasonic-assisted hot-press molding technology, micro-nano mechanical interlocking structure, tensile-shear strength