Additive manufacturing of textured ceramics: A review

Additive manufacturing (AM) is a powerful tool for fabricating ceramics with novel and/or improved properties by enabling access to unique part architecture and geometry, and control of pore structure and distribution. In this review we show that layer-wise and direct writing AM processes can be used to fabricate microscopically-textured ceramics with unique crystallographic orientations by combining templated grain growth (TGG) with manipulation of the rheological properties of the feedstock, printhead geometry and printing speed during layer-wise and direct writing AM processes. For TGG the shear gradient, and resultant local torque, during printing aligns anisotropically-shaped template particles which serve as substrates for subsequent oriented grain growth and increase in crystallographic texture in the final part during sintering. We show how the deposition flow field and rheology of AM feedstocks coupled with anisotropic printing nozzles enables enhanced template alignment by impacting the torque gradient during deposition. Prospects for AM of textured ceramics are presented.