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.