Fracture toughness and R-curve behavior of laminated ZrB2–SiC/SiCw ceramic

Abstract

Laminated ZrB2–SiC/SiCw (LZSw) was prepared via tap-casting and hot-pressing processes. The R-curve behavior of the ceramic materials was evaluated using indentation-strength method. The flexural strength and fracture toughness values of the materials were found to reach up to 607 MPa and 14.5 MPa·m1/2, respectively, when employing SiC whiskers as a strong interface. The indentation strength was observed to decrease upon an increase in the indentation load, and compared with the steep decreasing trend exhibited by the monolithic ZrB2–SiC (ZS20), LZSw showed a slow decreasing trend. LZSw showed a distinct upward trend in its R-curve, which was found to be dependent on the indentation collapse caused by its laminated structure and the increasing crack propagation path as a result of crack deflection and branching mechanisms.