| dc.description.abstract | Porous aluminum prepared by the metal hollow sphere method possesses a closed cell structure, offering advantages such as low density, high specific strength, and excellent compression properties. Its energy absorption capacity is several times that of commercial aluminum foam, making it highly promising for applications in ballistic or blast-resistant fields. A201 aluminum alloy (Al-4.5Cu-0.3Mg-0.7Ag) is the highest-strength casting aluminum alloy, primarily strengthened through precipitation strengthening heat treatment. This process involves the precipitation of strengthening phases Ω and θ′ to enhance the mechanical properties of the alloy. In practical applications, different heat treatment methods, such as T4 natural aging, T6 peak aging, and T7 overaging, can be applied depending on the specific requirements.
In this study, A201 aluminum alloy foam was prepared using Φ2mm 316L, Φ4mm 316L, and Φ4mm 4605 metal hollow spheres through pressure infiltration casting. After solution treatment and water quenching, various heat treatment processes, including T4 natural aging (RT*4day), T6 peak aging (155°C*20hr), and T7 overaging (185°C*5hr), were applied to investigate the influence of hollow spheres and heat treatment on the microstructure and mechanical properties (compression and hardness) of A201 aluminum alloy foam.
The results show that the microstructure of the as-cast porous aluminum consists of austenite for 316L and fine pearlite for 4605 in the hollow sphere walls, while the aluminum matrix microstructure is composed of α-Al, iron-rich phases, and a small amount of Al2Cu eutectic phases. After aging treatment, the precipitation strengthening effects of Ω and θ′ phases significantly increase the hardness of the aluminum matrix, with the most significant improvement observed in the T6 peak aging treatment. In terms of mechanical properties, due to the higher hardness of 4605 spheres, porous aluminum containing 4605 spheres exhibits superior compression properties compared to those containing 316L spheres. Furthermore, reducing the size of the hollow spheres has a positive effect on compression properties.
In summary, aluminum alloy foam containing Φ4mm 4605 hollow spheres, subjected to T6 peak aging treatment, achieves a plateau stress (σpl) of up to 190MPa and a specific energy absorption value (W) of 112J/cm3. This represents the best compression properties among the literature-reviewed porous aluminum materials. | en_US |