Mechanical properties of SiC‐C‐B 4 C composites with different carbon additives produced by pressureless sintering

In this research, carbon sources (Resin Phenolic, Carbon Black and Graphite) and Boron Carbide (B 4 C) were used to improve the mechanical properties of Silicon Carbide (SiC) composite. For this purpose, carbon sources of 0.5, 0.75, 1, 1.5, 2, 2.5, 3, and 5 wt% as well as 0.5 wt% B 4 C were added to SiC powder, respectively. The sample containing SiC—2.5 wt% Resin Phenolic—0.5 wt% B 4 C had the best properties with relative density, hardness, and fracture toughness values of 98.5%, 2820 GPa, and 3.9 MPa.√m, respectively. Examination of SEM images showed that by increasing carbon from 0.5 to 2.5 wt%, the fracture changes from intergranular to transgranular.