Preparation and interfacial layer microstructure of multilayer heterogeneous composite

Abstract

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 SiCf/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.