Nanoscale dynamic fracture mechanisms of columnar-grained SiC matrix in SiCf/SiC composites under tensile loading

This study investigates the dynamic mechanical behavior of matrix components in ceramic matrix fiber-reinforced composites at nanoscale. Experimental results indicate that the matrix mainly consists of columnar-grained β-SiC. Simulation results demonstrate a remarkable strain-rate strengthening effect under tensile loading: with increasing strain rate, more cracks are activated within the matrix, consuming more fracture energy and consequently enhancing tensile strength. The tensile strength exhibits an exponential relationship with the strain rate, reaching 1.73 times the quasi-static value when the strain rate increases to 1000 times the quasi-static level.