Improvement of the strength and toughness of carbon fiber/SiC composites via chemical vapor infiltration-grown SiC nanowire interphases

SiC nanowires (SiC_nws) were used to modify the interphase of carbon fiber/pyrocarbon/SiC(C_f/PyC/SiC) composites. These SiC_nws were grown in the carbon fiber preform via chemical vapor infiltration(CVI). The effects of these SiC_nw interphases on the microstructure and mechanical properties of C_f/PyC/SiC composites were investigated. According to the obtained results, the composites containing SiC_nw interphases(i.e., C_f/SiC_nw/PyC/SiC and C_f/SiC_nw/SiC) showed higher strength and toughness than C_f/PyC/SiC composites at both room and high temperatures. The superior pull-out and bridging crack characteristics of SiC_nws can account for the toughening of C_f/SiC and C_f/PyC/SiC upon growth of SiC_nw interphases, which resulted in composites with higher crack propagation resistances and superior load with standing capabilities.