SUMMARY

Ceramics serve as important engineering materials that have the ability to offer unique advantages over metals and polymers in various extreme-environment applications (e.g., high temperature, corrosion, radiation). This ability, however, has yet to be realized because ceramics are very susceptible to mechanical failure due to their inherent brittleness and low fracture toughness. In order to develop suitable ceramic parts, ultra-tough ceramics must be fabricated with complex geometries. To achieve this objective, a new additive manufacturing method is proposed here; the purpose of which is to establish the creation of a new field of additive manufacturing, which involves the fabrication of high-performance ceramics for demanding applications such as high-efficiency jet engines and next-generation nuclear reactors.

A multi-functional prototype system of the proposed method has been developed, which makes use of both the droplet-on-demand (DOD) and fused deposition modeling (FDM) printing technique. The build material consists of a liquid pre-ceramic polymer (PCP) that has been mixed with active fillers to counteract the porosity and shrinkage associated with PCPs during pyrolysis. To validate the system’s near-net-shape capabilities, microstructural analysis was executed. Mechanical testing of fabricated samples was performed to measure material properties such as Young’s modulus, hardness, and fracture toughness. The addition of carbon nanofibers (CNFs) into the build material was performed to investigate toughening enhancement of fabricated samples.

The results of the microstructural analysis and mechanical testing indicate that the proposed method can fabricate parts with near-net-shape capabilities and with fracture toughness similar to that of common engineering ceramics. Additionally, the prototype system shows that with increased concentration of CNFs, ultra-tough ceramic fabrication should be possible using the proposed method.