Influence of yttria-stabilized zirconia content on rheological behavior and mechanical properties of zirconia-toughened alumina fabricated by paste-based stereolithography

Improvement of the mechanical properties of advanced ceramics fabricated by additive manufacturing has been a prerequisite for their wide applications. In this work, zirconia-toughened alumina (ZTA) parts with a variety of yttria-stabilized zirconia (YSZ) content were fabricated by stereolithography (SL) technology, based on the appropriate self-holding ability of the viscoelastic paste and application of conformal contactless support strategy. Combining microstructural analysis and mechanical assessment by three-point bending and indentation tests, the influence of YSZ content on the SL process and subsequent mechanical properties was discussed. The results showed that the optimized matching of flexural strength (477.54 MPa) and fracture toughness (6.56 MPa m 1/2 ) was acquired by ZTA ceramic with a YSZ content of 20 wt%. When the YSZ content reached 30 wt%, agglomerations formed and led to a negative influence on the properties of ZTA ceramics. It is confirmed that the combined contribution from the addition of YSZ on the improvement of mechanical property and influence of the SL process should be synthetically considered during the design of ceramic paste feedstock for such additive manufacturing.