Effect of preparation process on layer-directional dynamic compressive properties of 3N C/SiC composites

In order to study the effect of different preparation processes on compressive mechanical properties, the compressive properties of 3N-C/SiC composites prepared by reaction melt impregnation (RMI) and chemical vapor impregnation (CVI) were investigated respectively at various strain rates, and compared the microstructure of the samples before and after failure. The results show that the failure strength of the two kinds of composite under high strain rate all obeys Weibull distribution, and RMI composites have a higher stability than the CVI composites. Both composites present an obvious strengthening effect on strain rate, meanwhile, the relationship between failure strength and logarithmic strain rate characterizes linear. According to the fracture morphology, the mixture of shear failure and delaminated failure leads to the failure under quasi-static compression, on the contrary, the failure mode of the composites under dynamic compression is splitting failure. In addition, fracture of the samples with RMI process is smoother than the samples with CVI. The phenomenon of debonding within bundle is inhibited obviously under dynamic loading for the samples with RMI process.