High hardness (TiZr)C ceramic with dislocation networks
Xiaojie Guo, Xiao‐Ting Xin, Weichao Bao, Xin‐Gang Wang, Qingqing Yang, Yi Zeng, Guo‐Jun Zhang, Fangfang Xu
Abstract
Abstract Raising the configurational entropy in a solid solution ceramic is regarded as a promising strategy to improve the mechanical properties of ceramics, especially when five or more elements are mixed to form so‐called high‐entropy ceramics. However, in this study, we report that the binary (TiZr)C solid solution ceramics can demonstrate high hardness comparable or even superior to high‐entropy ceramics. Followed by a carbothermal reduction synthesis of carbide powders, the bulk ceramics were synthesized by hot pressing. Via increasing the hot pressing temperature to 2200°C, a full solid solution of equimolar (TiZr)C was obtained in contrast to phase separation at lower sintering temperatures, for example, 2000 and 2100°C. The dislocation networks are observed in the single‐phase (TiZr)C ceramic and should be the product of competition between enthalpy and entropy in a binary full solid solution. These defects finally contribute to the high nano‐hardness of 41.9 ± 1.4 GPa ( H ) and the Vickers hardness of 22.0 ± 0.6 GPa ( H V at 49 N).