Additive Manufacturing of Fiber-Reinforced Zirconia-Toughened Alumina Ceramic Matrix Composites by Material Extrusion-Based Technology

Material extrusion-based additive manufacturing becomes interesting to fabricate oxide ceramic matrix composites. Herein, 0-30 vol% alumina fibers are added to zirconia-toughened alumina powder mixture and extruded into filaments. Shrinkage and mechanical properties of filaments and 3D-printed samples are investigated. Thermomechanical analysis is conducted on filaments with and without fiber content indicating lower shrinkage in the direction of fiber alignment during the sintering process. The flexural strength of the extruded filaments and printed bars is measured through a 4-point bending test. Filaments containing 15 vol% fiber exhibit the highest flexural strength of 110 MPa, with additional fiber content leading to a reduction in flexural strength. Using Weibull calculation, it is observed that printed bars without fibers result in significantly lower bending strength in comparison to the filaments because of the presence of printing failures. Bars with 10 vol% fibers, printed with 0 degrees infill orientation achieve the same mechanical properties as the filaments, even though in microcomputed tomography gaps between printed lines and voids between raster lines can be observed. These results demonstrate that fiber reinforcement of ceramics offers a great potential to avoid the reduction of mechanical properties by printing defects. Herein, thermoplastic extrusion-based additive manufacturing, previously referred to as fused filament fabrication or fused deposition modeling, is used to produce all-oxide ceramic matrix composites (O-CMCs). The flexural strength of the extruded filaments and printed bars is measured using a 4-point bending test. It can be concluded that printing defects in O-CMCs do not reduce the mechanical properties thanks to the activation of the toughening mechanism in O-CMCs.image (c) 2024 WILEY-VCH GmbH