The Matrix Cracking Stress and Residual Thermal Stress of 2D SiC/SiC Composite Fabricated by PIP Process

摘要

A two dimensional silicon carbide fiber reinforced SiC matrix (2D SiC/SiC) composite was fabricated by precursor infiltration pyrolysis (PIP) process used a liquid SiC ceramic precursor. Two key properties including matrix cracking stress and residual thermal stress were investigated for this PIP 2D SiC/SiC composite. Three methods were applied to determine the matrix cracking stress in order to obtained a trusted value, and the value of matrix cracking stress for SiC/SiC composite was 75 ± 4 MPa. The residual thermal stress of the composites was calculated by linear regression line according to the loading-unloading-reloading stress-strain curve of the 2D SiC/SiC composite, and the result showed that the value of residual thermal stress of SiC matrix in composite was 20MPa, which means the PIP SiC matrix in the 2D SiC/SiC composite was under the compressive stress when the composite cooling down from the fabrication temperature to the room temperature.