Research on the microstructure and mechanical properties of high‐entropy composite ceramics

Abstract To investigate the microstructure and mechanical properties of HEB‐SiC composite ceramics, various SiC contents (10 vol%, 20 vol%, 30 vol%) were incorporated as the second phase. (Mo 0.2 Nb 0.2 Zr 0.2 Hf 0.2 Ti 0.2 )B 2 ‐(10 vol%, 20 vol%, 30 vol%)SiC composite ceramics were synthesized using borothermal/carbothermal reduction followed by SPS. As the sintering temperature increased, the hardness of the composite ceramics remained relatively stable, while the fracture toughness showed a notable improvement. Additionally, with an increase in SiC content, the hardness of the composite ceramics decreased, whereas the fracture toughness increased. The highest hardness values were observed for the 10 vol% SiC samples, measuring 31.4 ± 1.4 GPa at 1800°C and 31.4 ± 1.3 GPa at 1900°C. The 30 vol% SiC sample sintered at 1900°C exhibited the highest fracture toughness, reaching 5.24 ± 0.44 MPa·m 1/2 . These findings demonstrate that increasing the SiC content enhances the mechanical properties of high‐entropy boride ceramics.