Synergistic effects of high-entropy alloy addition on hardness and fracture toughness of (Ti,Nb,Ta,Mo,W)(C,N)-based high-entropy ceramics

• Published in: Ceramics international Vol. 49; no. 21; pp. 33652 - 33658
• Main Authors: Zhou, Yu-Zhang, Huang, Kun-Heng, Bo, Guang-Xu, Luo, Si-Chun, Guo, Wei-Ming, Sun, Shi-Kuan, Lin, Hua-Tay
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2023
• Subjects: High-entropy alloy; High-entropy carbonitride ceramic; Mechanical properties; Microstructure; Mechanical properties; High-entropy carbonitride ceramic; Microstructure; High-entropy alloy
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2023.08.047

High hardness and high toughness (Ti,Nb,Ta,Mo,W)(C,N)-based ceramics were prepared using pre-synthesized high-entropy carbonitride (HECN) powder and high-entropy alloy (HEA) via spark plasma sintering. By HEA addition of 5 vol%, dense (Ti,Nb,Ta,Mo,W)(C,N)-based ceramics with fine microstructure was obtained at 1450 °C. Due to the presence of the precipitated (Mo,W)2C phase within the HECN matrix, which forms a solid solution with the added HEA, the ceramics exhibited the high Vickers hardness (24.5 ± 1.3 GPa) and fracture toughness (6.1 ± 0.4 MPa m1/2), arise from the fine grain structure of the ceramics and the pronounced effect of crack deflection. This study introduced a new strategy for the preparation of high-entropy carbonitride-based ceramics, which significantly improved the fracture toughness while maintained high hardness.