Recent advances and future trends in processing methods and characterization technologies of aluminum foam composite structures: A review

Aluminum foam composite structures, represented by sandwich plates and filled tubes, process remarkable light-weight and energy absorption characteristics, which have increasing demands for designing novel lightweight structures. However, the continuous forming of aluminum foam composite structures faces various challenges that limit rapid development, such as high preassemble precision, poor interfacial bonding strength, limited product size, difficult pore miniaturization, uneven performance, low production efficiency, etc. This paper provides a comprehensive overview of recent advances in processing methods and characterization technologies of aluminum foam composite structures. First, processing methods of both aluminum foam and composite structures are introduced, compared, and classified. The bonding mechanisms, essential to connect the solid cladding and foam core, are analyzed, and the limitations are revealed. Then, bubble stability theory, porous structure control, three-dimensional reconstruction, mesostructure modeling, and performance characterization are reviewed, which are important to quantify structural characteristics and functional characteristics. Subsequently, the process development technical route and the full life cycle design theory system are discussed. The blowing-converging continuous casting process and the twin-roll continuous cast-rolling process are proposed to obtain continuous near-net forming of aluminum foam composite structures. Ultimately, contemporary challenges and future directions for aluminum foam composite structures are discussed. Two key scientific questions need to be addressed urgently. One is the evolution law and continuous forming mechanism of the solid-liquid-gas multiphase interface, and the other is the structure-performance synergistic control strategy of solid cladding, bonding interface, and foam core. This synopsis provides a useful platform for researchers and engineers to develop novel processing methods for aluminum foam composite structures and use emerging technologies to investigate their comprehensive properties.