Microstructure and properties of dense Tyranno-ZMI SiC/SiC containing Ti3Si(Al)C2 with plastic deformation toughening mechanism

In this paper, Ti3Si(Al)C2 was introduced into dense SiC/SiC to improve the mechanical and electromagnetic interference (EMI) shielding properties. In order to reveal the effect of Ti3Si(Al)C2, dense SiC/SiC-Ti3Si(Al)C2 and dense SiC/SiC without Ti3Si(Al)C2 were fabricated. Owing to the plastic deformation toughening mechanism of Ti3Si(Al)C2, SiC/SiC-Ti3Si(Al)C2 performs a new damage mode characterized by matrix/matrix (m/m) debonding. High interfacial shear strength (IFSS) due to large thermal residual stress (TRS) is weakened by m/m debonding. This new mode also brings high effective volume fraction of loading fibers and long path of crack propagation. Hence SiC/SiC-Ti3Si(Al)C2 exhibits higher flexural strength (503 MPa) and fracture toughness (23.7 MPa · m1/2) than the dense SiC/SiC without Ti3Si(Al)C2. In addition, dense SiC/SiC-Ti3Si(Al)C2 shows excellent electromagnetic interference shielding effectiveness (EMI SE, 43.0 dB) in X-band, revealing great potential as thermo-structural and functional material.