Improved fracture toughness of laminated ZrB2-SiC-MoSi2 ceramics using SiC whisker

摘要

In this study, SiC whisker (SiCw) was introduced to ZrB2 matrix layer of laminated ZrB2/BN ceramics to improve fracture toughness. Laminated ZrB2-SiCw/BN ceramics were prepared by tape casting and spark plasma sintering. For comparison, monolithic ZrB2-SiCw and laminated ZrB2-SiCp/BN ceramics were also prepared using the same method. The introduction of SiC whiskers increased fracture toughness of laminated ZrB2-SiCw/BN ceramics to 13.31 +/- 0.33 MPa m(1/2) for all samples. This was related to the multi-scale toughening mechanism, including delamination and crack deflection issued from the laminate structure at the macroscopic level, as well as whiskers bridging and pullout at the microscopic view. The R-curve behaviors of all samples revealed improved resistance to crack propagation of laminated ZrB2-SiCw/BN when compared to ZrB2-SiCp/BN and ZrB2-SiCw issued from multi-scale toughening design.