Li Hao, Yang Zhenxing, Lian Min, Ma Shuailing, Li Wei, Wei Xinmiao, Zhao Xingbin, Pan Yilong, She Yunfeng, Dang Lingyan, Yuan Bao, Cui Tian
School of Physical Science and Technology, Institute of High-Pressure Physics, Ningbo University, Ningbo 315211, China.
College of Science, Hebei North University, Zhangjiakou 075000, China.
Materials (Basel). 2025 Apr 4;18(7):1655. doi: 10.3390/ma18071655.
High-entropy ceramics (HECs) have garnered considerable interest due to their exceptional mechanical properties and high-temperature stability. Nevertheless, their inherent brittleness significantly restricts industrial applications, posing a challenge to improving toughness without compromising hardness. This study investigates the role of SiC whiskers (SiCw) in simultaneously suppressing grain growth and enhancing the toughness of high-entropy (TiZrHfNbTa)C (HEC) composites, while maintaining high hardness during high-pressure high-temperature (HPHT) sintering. HEC-SiCw composites were fabricated via HPHT (P = 5 GPa, T = 2000 °C), with SiCw contents ranging from 0 to 40 mol%. As the SiCw content increased, the growth of HEC grains was inhibited, and the fracture toughness progressively rose to a peak value (K = 9.4 ± 1.2 MPa·m), representing an increase of approximately 184% compared to that of pure HEC, while Vickers hardness remained stable at 26 GPa. The enhancement in fracture toughness is attributed to the heterogeneous grain distribution and robust grain boundary strength, which facilitated a synergistic combination of transgranular and intergranular fracture mechanisms. These mechanisms induced crack deflection and whisker pull-out, effectively dissipating fracture energy and impeding crack propagation, thereby enhancing toughness. This study presents a novel approach to simultaneously refine grain size and improve toughness in HECs through HPHT processing, providing valuable insights for the development of next-generation ceramic composites.
高熵陶瓷（HECs）因其优异的力学性能和高温稳定性而备受关注。然而，其固有的脆性严重限制了工业应用，在不降低硬度的情况下提高韧性成为一项挑战。本研究探讨了碳化硅晶须（SiCw）在高压高温（HPHT）烧结过程中同时抑制晶粒生长和提高高熵（TiZrHfNbTa）C（HEC）复合材料韧性的作用，同时保持高硬度。通过HPHT（P = 5 GPa，T = 2000 °C）制备了HEC-SiCw复合材料，SiCw含量范围为0至40 mol%。随着SiCw含量的增加，HEC晶粒的生长受到抑制，断裂韧性逐渐上升至峰值（K = 9.4 ± 1.2 MPa·m），与纯HEC相比增加了约184%，而维氏硬度保持在26 GPa稳定。断裂韧性的提高归因于晶粒的非均匀分布和强大的晶界强度，这促进了穿晶和沿晶断裂机制的协同组合。这些机制导致裂纹偏转和晶须拔出，有效地耗散断裂能量并阻碍裂纹扩展，从而提高韧性。本研究提出了一种通过HPHT工艺同时细化HECs晶粒尺寸和提高韧性的新方法，为下一代陶瓷复合材料的开发提供了有价值的见解。
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