Using PyC coated short chopped carbon fiber to tackle the dilemma between toughness and strength of ZrC-SiC

Abstract

Graceful toughness and high strength are mutually exclusive in engineering ZrC-SiC ceramic, which are hard to be possessed simultaneously. Here, the pyrolytic carbon (PyC) coated short chopped carbon fibers were utilized to toughen ZrC-SiC ceramic, tackling the dilemma between toughness and strength. Through the uniform incorporation of PyC coated short chopped carbon fibers, the penetration crack mode of ZrC-SiC was changed into an obviously deflecting propagation path with closed phenomenon. The PyC coating brought about a relatively weak interface bonding and guided the crack propagate along the weak interface, consequently resulting in a more flexuous crack propagation instead of passing through the fibers directly. Meanwhile, the fibers received effective protection of coating inhibiting from performance degradation. The PyC coated Cf/ZrC-SiC obtained a fracture toughness highly reaching 7.57 ± 0.33 MPa m1/2 with a rivaling flexural strength at 268 ± 16 MPa. Moreover, the graceful load-displacement curve is illustrated with a smoothly extended displacement of 0.12 mm and increased load to 83 N, which forms an obvious yield plateau. To some degree, this work provided an effective solution to tackling the dilemma between toughness and strength of engineering ZrC-SiC ceramic.