High-temperature tensile behavior of 3D SiC/SiC composites

Abstract

The high-temperature tensile properties and stress-strain behavior of a 3D SiC/SiC composites prepared by the PIP method were investigated. Based on the FESEM analysis of the fracture morphology, the tensile failure mechanism of the composite at elevated temperature was discussed. The results show that the tensile strength of SiC/SiC composites showed a significant decline for specimens from a room temperature value of 482.5 MPa, to 167 MPa and 138 MPa at 1100 °C and 1300 °C, respectively. The toughening mechanism of composites at 1100 °C, including interface debonding, long pull-out fibers, and fracture mirror characteristics, is consistent with the pseudo-plastic fracture behavior implicated in the stress-strain curve. As a result of more significant oxidation, the fracture morphology of the specimen tested at 1300 °C was characterized by the signs including fiber-to-fiber bonding, larger size glassy phase, and shorter fiber pull-out length.