Abstract

This article presents an innovative additive manufacturing approach for fully optimized ceramic and hybrid (ceramic/polymer) hierarchical micro-architected materials for extreme environments. The developed materials combine high-temperature capabilities, extremely low thermal conductivity, high stiffness and strength per unit weight, sufficient toughness and great resistance to oxidation. Processing involves 3D printing of a ceramic architecture, followed by bisque firing and sintering. When sufficient porosity remains after sintering (~50%), infiltration by a polymeric matrix is possible, resulting in a cellular architecture where the constituent material is a fully dense ceramic/polymer hybrid with exceptional ductility. After characterizing the microstructure and mechanical properties of the constituent material (ceramic and hybrid), we demonstrate the fabrication of a truss-core sandwich panel. Both the internal architecture and the external shape can be controlled at will in the manufacturing process. Multifunctional Thermal Protection Systems (TPS) for the next generation of high-speed aircraft (particularly hypersonics) are the prototypical, albeit not the only, application.