Interfacial evolution and strengthening mechanism in DLP 3D-Printed In718/SiBCN cermet composites via in-situ reaction

Metal-ceramic composites have emerged as a research hotspot due to their combined advantages of both ceramic and metallic properties. This study presents an innovative strategy for fabricating In718/SiBCN cermet composites via light-curing 3D printing and systematically investigates their mechanical properties, interfacial structure, and strengthening mechanisms. The results demonstrate that the composites exhibit outstanding performance, including a low density of 6.89 g/cm 3 , a high flexural strength of 751.68 MPa, and a specific strength of 109.10 MPa/g/cm 3 . Notably, chromium precipitates from the metal and undergoes a carburization reaction, forming Cr 23 C 6 in situ. This carbide exists as a precipitate phase within the metallic matrix, establishing a strong interfacial bond with the matrix. Nanoindentation measurements reveal that the average hardness and modulus of the composites reach 12.85 GPa and 216.23 GPa, respectively, which are significantly higher than those of monolithic SiBCN and In718. Finally, the fracture mechanisms indicate that cracks propagate along the secondary phase particles in a transgranular manner, promoting crack deflection and generating extensive microcracking. These mechanisms facilitate substantial energy dissipation, thereby markedly improving both the strength and toughness of the composites.