Fabrication and mechanical properties of 3D printed nacre-inspired Al2O3-ZrO2 composite ceramics

In the field of engineering materials , achieving a balance between high strength and high toughness often poses a challenge. Typically, enhancing the toughness of ceramics involves incorporating a ductile metallic or polymeric phase; however, their application in high-temperature environments is constrained. Inspired by the biological materials, this work proposes all-ceramic composite with nacre-like structure, which was prepared utilizing 3D printing technology . Flexural strength was tested by three-point bending and fracture toughness was determined by SEVNB. The crack growth resistance capability was evaluated using the J-integral method. The effects of the content of polymethyl methacrylate (PMMA) microspheres in the weak phase and volume fraction of the strong phase on the flexural strength, fracture toughness, and progressive failure behavior of nacre-inspired composite ceramics were elucidated. The nacre-inspired Al 2 O 3 -ZrO 2 composite ceramics were found to exhibit non-brittle failure due to the layered features, whilst the Al 2 O 3 -ZrO 2 composite ceramics fractured catastrophically, though it is expected to have a higher failure stress. The step-like fracture mode enhances energy dissipation during crack propagation , thereby resulting in a higher fracture toughness of the nacre-inspired Al 2 O 3 -ZrO 2 composite ceramics compared to Al 2 O 3 -ZrO 2 composite ceramics. The findings can serve as valuable guidance for the design and fabrication of nacre-inspired composites.