Mechanical properties of 3D-printed Al2O3 honeycomb sandwich structures prepared using the SLA method with different core geometries

In this study, Al2O3 honeycomb sandwich structures with different core geometries (square, triangular, circular) have been fabricated through an additive manufacturing system based on the stereolithography (SLA) method. The debinding procedure was performed under both nitrogen and air atmospheres. The impacts of the debinding atmosphere and core geometry on the densification and mechanical properties were investigated. The stiffness and flexural strength of the ceramics were examined experimentally using an impulse excitation of vibration technique and a three-point bending test, respectively. The specific stiffness and specific strength of the ceramics were also evaluated, with the core geometries taken into consideration. The outcomes showed that higher densification was achieved when the ceramics were exposed to debinding in nitrogen. The stiffness values were found to be similar for the same debinding condition within the honeycomb sandwich structures, irrespective of the core geometry. Notably, the highest specific stiffness (98 MNm/kg) was achieved for the samples subjected to debinding in nitrogen with a square core geometry. Furthermore, ceramics with square cores for debinding in a nitrogen atmosphere also demonstrated the highest performance in terms of specific strength (110 kNm/kg) within the honeycomb structures. This study demonstrated that Al2O3 honeycomb sandwich structures with square cores may be suitable candidates for lightweight-structure demanding applications.