Mode I fracture toughness of short carbon fiber-dispersed SiC matrix composite fabricated by melt infiltration process

Abstract

Measurement of mode I fracture toughness of in-plane random oriented short carbon fiber-dispersed SiC matrix composite fabricated by melt infiltration process has been carried out. Fracture toughness (KIc) measured using a Brazilian disk specimen is ~3.5−4.1MPam, which is comparable to those of monolithic engineering ceramics. The measured toughness is explained using average stress and characteristic length (χD) of damage zone formed ahead of notch tip: KIc≈σFπχD/2. Crack arrest behaviors in the short carbon fiber-dispersed SiC mini-composite play an important role on the stability of micro-cracks in the damage zone before unstable crack growth.