Fracture behavior and mechanism of 2D C/SiC-BCx composite at room temperature

2D C/SiC composite was modified with partial BC_x matrix by low pressure chemical vapor infiltration technique (LPCVI), which was named as 2D C/SiC-BC_x composite. The flexural fracture behavior, mechanism, and strength distribution of 2D C/SiC-BC_x composite are investigated. The results indicate that the flexural strength, fracture toughness, and fracture work are 442.1 MPa, 22.84 MPa m^1/2, and 19.2 kJ m⁻², respectively. The flexural strength of C/SiC-BC_x composite decrease about 20% than that of C/SiC composite. However, the fracture toughness and fracture work increase about 19% and 18.5%, respectively. The properties varieties between C/SiC-BC_x composite and C/SiC composite can be attributed to the weak-bonding interface between BC_x/SiC matrices according to the results of detailed microstructure analysis. The strength distribution of 2D C/SiC-BC_x composite follows as Normal distribution or Weibull distribution with σ_u = 0, and m = 8.1393. The mean value of flexural strength for 2D C/SiC-BC_x composite is 443 MPa obtained by theory calculation, which is consistent with experiment result (442.1 MPa) very well.