Low-temperature sintered (Ti, Zr, Nb, Ta, Mo)C-based composites toughened with damage-free SiCw

The high sintering temperature would have a great tendency to damage the morphology and thus properties of the silicon carbide whisker (SiCw) in high entropy carbide-silicon carbide whisker (HEC-SiCw) composites, which, in turn, would impact the effectiveness of the operative toughening mechanisms. The objective of this study was to achieve full contributions to the toughening effects of SiCw by preparing (Ti, Zr, Nb, Ta, Mo)C-SiCw composites at low temperature (1600 degrees C) using cobalt as additives. Results showed that the fracture toughness of the (Ti, Zr, Nb, Ta, Mo)C bulk reinforced with 20 vol% SiCw and 5 vol% Co was 7.2 MPa center dot m1/2, which was much higher than that of the (Ti, Zr, Nb, Ta, Mo)C bulk only sintered with 5 vol% Co (3.4 MPa center dot m1/2). Meanwhile, it was also higher than that of the reported HEC-20 vol% SiCw composite sintered at 2000 degrees C (4.3 MPa center dot m1/2). For the fracture toughness of HEC-SiCw composites, it was significantly increased by the introduction of damage-free SiCw.

Automated summary

The high sintering temperature can damage the morphology and properties of SiCw in HEC-SiCw composites, which affects the toughening mechanisms. This study aims to maximize the toughening effects of SiCw by preparing (Ti, Zr, Nb, Ta, Mo)C-SiCw composites with cobalt as additives at low temperature (1600 degrees C). Results showed that the fracture toughness of the (Ti, Zr, Nb, Ta, Mo)C bulk reinforced with 20 vol% SiCw and 5 vol% Co was 7.2 MPa·m1/2, higher than that of (Ti, Zr, Nb, Ta, Mo)C bulk sintered with only 5 vol% Co (3.4 MPa·m1/2) and HEC-20 vol% SiCw composite sintered at 2000 degrees C (4.3 MPa·m1/2). Introduction of damage-free SiCw significantly increased the fracture toughness of HEC-SiCw composites.