Synthesis-structure-property relationships in AA6061 periodic cellular materials

Periodic cellular materials (PCMs) can have high specific strengths and stiffness at low density, making them an attractive materials design option. Micro-truss PCMs can be fabricated through simple sheet forming operations of perforated starting materials. This study is divided into two parts: formability and mechanical testing. Square-punched AA6061 perforated sheets were subjected to a range of treatments: solutionizing (W), artificial ageing at 205°C (T6), and full annealing (O). The range of attainable pyramidal architectures is presented for each condition. Fully annealed sheets provide the greatest formability but would require a post-fabrication solutionizing treatment to benefit from the AA6061's precipitation hardening capabilities. Conversely, fabrication from the W temper allows the post-forming strain hardening to be used as a microstructural design tool. Mechanical testing showed that thermomechanically treated (T8) samples generally show improved mechanical properties, combining both work-hardening from the micro-truss fabrication and precipitation hardening.