Crack initiation and propagation in a high-solid-loading ceramic core fabricated through stereolithography 3D printing

Ceramic cores are applied in electronics, aerospace, medicine, military, automotive, and other fields. However, the effects of the build direction, along with the shrinkage of the green body and thermal stress, on the mechanical properties of 3D ceramic cores have not been elucidated. To reveal the optimum conditions for crack resistance in a high-solid-loading ceramic core, a silicon-based ceramic core with a solid content of 60 vol% was fabricated through stereolithography 3D printing and analyzed in terms of its microstructure-level crack initiation and propagation. The green bodies were initially 3D printed in different build directions (length-directed, width-directed, and height-directed) and then sintered at different temperatures (1100 °C-1250 °C). Higher sintering temperatures generally produced more cracks, and the synergistic effects of the sintering temperature and build direction induced crack initiation and propagation. The width-directed sample sintered at 1200 °C, in particular, exhibited effectively controlled crack growth without sacrificing strength.