Thermal shock resistant 3D-printed ceramic components through spatially tailored porosity

Planar layered ceramics designed with porous interlayers or weak interfaces have proved effective against the catastrophic failure associated with crack deflection mechanisms triggered by porosity. In this work, we explore the capabilities of spatially tailoring porosity in 3D-printing ceramic components, using the layer-by-layer vat photopolymerization process, to enhance damage tolerance. Porous interlayers or porous gradient regions are introduced in the structures by using a polymeric pore forming agent, which is removed after the debinding process. Multi-layered designs featuring varying porosity content are fabricated with both discrete and gradient interfaces. These designs are then subjected to biaxial bending tests, both before and after thermal shock testing, to assess the retained bending strength as a function of porosity. An optimized design is applied onto a welding nozzle to demonstrate the potential of combining dense and porous regions in complex 3D-printed ceramic parts to enhance their thermal shock resistance, opening a new pathway in designing structural ceramics with higher specific strength.