Preparation and interfacial layer microstructure of multilayer heterogeneous composite

The appropriate hetero interfacial layer structure between metal and ceramic matrix composites is a very interesting topic in materials science. In this work, an adaptive diffusion reactive interfacial layer composed of “Mo–Mo₂C–Mo₅Si₃–MoSi₂–SiC” between Mo and SiC_f/SiC composite is successfully prepared by chemical vapor infiltration (CVI). This reactive interfacial system is among three possible structures of interfacial layers predicted by Density-functional theory (DFT) calculations, which has the largest total interfacial energy (5.679 J/m²). At the same time, the formation process of the reaction interface layers is elucidated by thermodynamic calculations. In addition, dislocations are observed in Mo₅Si₃ and Mo₂C grains, and it is worth mentioning that the Mo₅Si₃ grains are broken through dislocation movement to form fine grains, which release the residual thermal stress of the interfacial layer system caused by thermal mismatch during the long-term CVI process. Overall, our work provides a practical strategy for developing multilayer heterogeneous composites.