Effects of SiC nanowires and whiskers on high‐entropy carbide‐based composites sintered at low and high temperatures

Abstract This study aimed to investigate the toughening effects of SiC nanowires (SiC nw ) and SiC whiskers (SiC w ) on high‐entropy carbide based composites prepared at different temperatures (1600°C and 2000°C). At low temperature (1600°C), SiC nw and SiC w maintain their original morphology and properties, and exhibit the good toughening effects. The SiC nw with larger aspect ratio and more curly wires exhibit a much stronger toughening effect on the (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 Mo 0.2 )C 0.8 composites reinforced with 15 vol.% SiC nw , which shows the highest value of fracture toughness about 6.7 MPa∙m 1/2 . However, at high sintering temperature (2000°C), SiC nw and SiC w are prone to thermal‐induced damages, which significantly reduces their mechanical properties, and thus, toughening effects on (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 Mo 0.2 )C 0.8 composites. The addition of SiC w , which have better thermal stability at 2000°C, results in the (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 Mo 0.2 )C 0.8 –15 vol.% SiC w composite exhibiting relatively better fracture toughness, about 3.7 MPa∙m 1/2 . Based on the results of the current study, the critical influence of SiC nw and SiC w on the toughening of (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 Mo 0.2 )C 0.8 composites is highly dependent on their high‐temperature thermal stability.