Processing and Mechanical Behavior of 3D Printed Ceramic Lattices and Their Derived Interpenetrating Phase Composites

Ceramics and their derived composites which are lightweight and with high strength and high toughness have been long sought after for various engineering applications. In this work, various alumina ceramic based microlattices, including Simple Cubic, Octet Truss and Kelvin Cell have been fabricated using computer-aided design tool and stereolithography 3D printing process, Subsequently, interpenetrating phase composites (IPCs), with the ceramic lattices as backbone and infiltrated with a second phase (e.g., epoxy or aluminum alloy), have been further developed. The mechanical behavior of the ceramic lattices and the IPCs under quasi-static compression tests has been systematically studied by experiments and simulation. Results show that Simple Cubic lattices generally initiate the fractures at the struts in the outermost lattice planes, while the Octet Truss and Kelvin Cell lattices fracture at the (110) diagonal plane. With a second phase infiltrated into the lattices, the resultant composites inherit similar fracture behavior as their corresponding lattices, but in a more gradual manner. The stiffness and compressive strength of the lattices follow the order of Simple Cubic > Octet Truss > Kelvin Cells. The compressive strength of IPCs is generally higher than that of the ceramic lattices. Composites with 50 vol% alumina simple cubic lattices and filled with epoxy exhibit a high compressive strength of 440 MPa and energy absorption of 12 J/g (at 16% strain). The energy absorption is almost 100% higher than that of epoxy and much better than that of the ceramic lattices. The factors controlling the mechanical properties of the lattices and IPCs, including relative density, topology, matrix materials and lattice defects arising from 3D printing, will be discussed and the perspectives on the application of the lattices and IPCs will be given in the presentation.