Preparation and mechanical properties of aluminum alloy 5a02/cfrtp laminates

Aerospace and military defense fields are posing higher requirement on the lightweight feature of structures. Subject of this study is the Aluminum Alloy 5A02 /CFRTP (Carbon Fiber Reinforced Thermo-Plastic) laminates. In the paper, aluminum alloy was anodized, compression molding and 3D printing were adopted to prepare Carbon Reinforced Aluminum Laminates (CARALL) with two different structures: the solid core structure and the honeycomb structure, and the prepared specimens were then tested for mechanical properties via tensile test and three-point bending test, and compared with the performance of the conventional aluminum alloy. The results show that under the condition of a same thickness, the tensile strength of CARALL specimens with the molded solid core structure and the 3D printed honeycomb structure reaches 256Mpa and 186MPa, respectively, which is 85.5% and 34.8% higher than that of the tensile strength of Al 5A02; under different bending modes, the maximum bending strength is 682Mpa and 525Mpa, respectively, which is 62.4% and 25.5% higher than that of Al 5A02. When the specimens are subject to tensile force, the separation of the metal layer and the fiber layer is the primary failure form, the fiber layer fractures, and the metal layer exhibits the necking phenomenon as the metal fibers are being pulled out. During the bending process, for different bending forms, there’re great differences in the bending strength of CARALL specimens prepared by the same method, the failure modes of the specimens vary greatly as well, and this is determined by the tensile strength of the carbon fiber layer and the tensile strength of AL 5A02. Enhancing the bonding strength between the metal layer and the fiber layer can improve the mechanical properties of CARALL. These research findings can provide a reference for the lightweight design of metals and Fiber Metal Laminates (FMLs).

Keywords
lightweight; CARALL (Carbon Reinforced Aluminum Laminates); compression molding; 3D printing; honeycomb structure