The effects of preparation temperature on the SiCf/SiC 3D4d woven composite

Abstract

Continuous silicon carbide fiber reinforced silicon carbide matrix (SiCf/SiC) composites have promising applications in aero-engine due to their unique advantages, such as low density, high modulus and strength, outstanding high temperature resistance and oxidation resistance. As SiC fibers are main reinforcements in SiCf/SiC composites, the crystallization rate and initial damage degree of SiC fibers are seriously influenced by preparation temperatures of SiCf/SiC composites, namely mechanical properties of SiC fibers and SiCf/SiC composites are influenced by preparation temperatures. In this paper, KD-II SiC fibers were woven into 3D4d preforms and SiC matrix was fabricated by PIP process at 1100 °C, 1200 °C, 1400 °C and 1600 °C. Digital image correlation (DIC) method was adopted to measure the uniaxial tensile properties of these SiCf/SiC composites. In addition, finite element method (FEM) based on representative volume element (RVE) was adopted to predict the mechanical properties of SiCf/SiC composites. The good agreements between numerical results and experimental results of uniaxial tensile tests verified the validity of the RVE. In last, the transverse tensile, transverse shear, uniaxial shear properties were predicted by this method. The predicted results illustrated that axial tensile, transverse tensile and axial shear properties were greatly influenced by the preparation temperatures of SiCf/SiC composites while transverse shear properties were not significantly various. And the mechanical properties of SiCf/SiC composites peaked at 1200 °C among these four temperatures while their values reached their lowest points at 1600 °C because of thermal damage and brittle failure of SiCf/SiC composites.