Simultaneous hardening and toughening of a high‐entropy (NbTaZrW)C ceramic carbide using SiC particle
Fei Peng, Zhen Wei, Qianqian Song, He Liu, Fengfeng Dai, Weidong Zhang, Zhenggang Wu
Abstract
Abstract Previously, we have found that (NbTaZrW)C exhibits a good combination of nanohardness and toughness. In this report, we explore the possibility to further increase the overall properties of this high‐entropy carbide ceramic (HECC) through introducing SiC particle (SiC P ). To this end, a series of (NbTaZrW)C– x SiC ceramic composites ( x = 0/5/15/30/50 vol.%) were fabricated using spark plasma sintering (SPS), their microstructure and mechanical properties were characterized. Our results reveal a grain refinement effects of SiC P , an agglomeration of SiC P with (1 0 0) plane preferentially perpendicular to the SPS‐pressing direction and the formation of a transition region with various stoichiometric ratio of (NbTaZrW) x C 1− x in the (NbTaZrW)C–SiC P vicinity. The elastic modulus, microhardness, and flexural strength of the HECCs show tight positive relations with the SiC P content and the beneficial effect of SiC P to the fracture toughness of (NbTaZrW)C becomes evident once the content of SiC P reaches 30 vol.%. Altogether, (NbTaZrW)C–50%SiC, which has a microhardness of 22 GPa, a flexural strength of 455 MPa, and an indentation fracture toughness of 6.54 MPa m 1/2 , presents the optimal combination of mechanical properties among the investigated composites. Mechanistically, the strengthening effect of SiC P introduction arises from the intrinsic high hardness of SiC P and the SiC P ‐induced grain refinement and the toughening effect is mainly associated with crack bridging mechanism.