Micro-architected Metallic Metamaterial Composites by Data-driven Generative Design and Binder Jetting Additive Manufacturing

This study describes a novel design and manufacturing approach for an optimized two-phase aluminum matrix, silicon carbide-reinforced cellular metamaterial composite with a low coefficient of thermal expansion (CTE). The design was generated with Bayesian optimization to obtain a periodic cellular pattern with the minimum coefficient of thermal expansion. The manufacturing was achieved via binder jetting additive manufacturing, followed by liquid aluminum infiltration. The barrier coating layer of Si-SiO 2 and the cooling rate after infiltration were found to be critical for suppressing the reaction between the two phases and maintaining the silicon carbide phase. A comparable study found that a proactive cooling rate as high as 20 °C/min could maintain a phase fraction of silicon carbide up to 12 wt.% in the manufactured composite, leading to minimized CTE values in multiple cycles of a single sample and repeatable values across various samples. The thermal cycling test validated the performance of the manufactured composite at high temperatures up to 350 °C. This study explored the design-manufacturing-test route for a novel metallic metamaterial composite, opening a wide research direction for advanced materials in harsh environments.