Mechanical properties of SiC whiskers reinforced SiC_f/SiC composites

Abstract

Multi-stage reinforced SiCf/SiC-SiCw composites were prepared by introducing SiC whiskers into SiCf/SiC composite, and BN interphase was deposited on the surface of SiC whiskers by chemical vapor infiltration (CVI). The mechanical properties of composites were evaluated. The results show that the compressive strength of the composites can be significantly improved on account of the reinforcing mechanism of SiC whiskers, such as the whisker pull-out, whisker bridging and crack deflection, which can extend the crack propagation path and increase the energy consumption capacity. The compressive strength of the composites is increased from 549.7 MPa to 673.9 MPa, with an increase of 22.6%, when the addition of SiC whisker is 20%(volume fraction). After depositing the BN interphase on SiC whiskers, the tensile strength, flexural strength and fracture toughness of the composites were 414.0 MPa, 800.3 MPa and 22.2 MPa·m1/2,which are increased by 13.9%,8.8% and 19.0%, respectively, compared with the composite reinforced with the uncoated whisker.

Keywords

• ceramic matrix composite
• sic whisker
• mechanical property
• bn interphase