High toughness of 3D printed ceramic/polymer interpenetrating phase composite with gradient structures under multi-directional stresses

Zirconia possesses high strength and good biocompatibility, but the inherent brittleness limits its further application. Inspired by the biomimetic structures, the interpenetrating phases have been demonstrated a toughening effect on brittle ceramic. In practical application, materials are subjected to stresses in different directions, which makes the toughening of materials more complex. This work reports a method of fabricating ceramic/polymer composite by 3D printing, and proposes three gradient structures with varying porosity in Z/XY/XYZ different directions for toughening. Composite infiltrated with hard-tough polymer prevents catastrophic failure and shows an increase of 400% in toughness. Under different directions of stresses, composites with gradient structures all display an enhancement in toughness compared with the uniform structure. The gradient changes in Z/XY/XYZ are able to achieve high toughness under multidirectional stresses, meeting the requirements of practical applications in different fields.