Quasi-static compressive and cyclic dynamic impact performances of vat photopolymerization 3D printed Al₂O₃ triply periodic minimal surface scaffolds and Al₂O₃/Al hybrid structures: Effects of cell size

In this study, Al₂O₃ triply periodic minimal surface (TPMS) scaffolds with cell sizes of 5 mm, 8.5 mm, and 12 mm were prepared by vat photopolymerization 3D printing, and Al₂O₃/Al ceramic-metal hybrid structures were subsequently obtained by the metal infiltration of AlSi10Mg. To investigate the influence of cell size on the mechanical properties of vat photopolymerization 3D printed Al₂O₃ TPMS scaffolds and Al₂O₃/Al hybrid structures, quasi-static compression and dynamic impact experiments were conducted, and the failure modes during experiments were discussed. It was shown that the quasi-static compression and dynamic impact properties of Al₂O₃ TPMS scaffolds gradually decreased with the increase in cell size, the compression strength decreased from 15.2 MPa to 8 MPa and the impact strength decreased from 37 MPa to 11 MPa, respectively, which was related to the stress transfer ability of the single cell. In contrast, the effects of cell size on the performance of Al₂O₃/Al hybrid structures were opposite. When the cell size increased, the quasi-static compression performances of the Al₂O₃/Al hybrid structure were greatly improved, and the compression strength increased from 175 MPa to 250 MPa. The impact resistances of the Al₂O₃/Al hybrid structure were further studied. The highest impact strength of the Al₂O₃/Al hybrid structure was 290.74 MPa. With the increase in cell size, the impact resistance of the Al₂O₃/Al hybrid structure had a gradual improvement trend. Under the cyclic impact, the Al₂O₃/Al hybrid structure showed a high impact strength and energy absorption capacity, which was mainly related to the metal phase content around the cell, i.e., the coherence of the metal phase. This study is believed to give help for the structural design of ceramic scaffolds and ceramic-metal hybrid structures.