Synthesis and mechanical and elevated temperature tribological properties of a novel high-entropy (TiVNbMoW)C 4.375 with carbon stoichiometry deviation

作者：Jicheng Li, Yanchun Zhou, Yunfeng Su, Shuna Chen, Qiuan Sun, Hengzhong Fan, Junjie Song, Litian Hu, Yongsheng Zhang · 发表于：Journal of Advanced Ceramics · 年份：2022 · DOI：10.26599/jac.2023.9220679 · 被引用次数：63 · 研究领域：Advanced materials and composites、High Entropy Alloys Studies、Metal and Thin Film Mechanics

High-entropy carbides are a nascent group of ceramics that are promising for high-temperature applications due to the combination of good stability, high hardness (H), high strength, and superior creep resistance that they display. Due to high melting points and low lattice diffusion coefficients, however, the high-entropy carbides are usually difficult to consolidate to a nearly full density. To cope with this challenge, herein, binary carbides including TiC, V8C7, NbC, Mo2C, and WC with different carbon stoichiometry were used to prepare dense high-entropy (TiVNbMoW)C4.375, and the influence of carbon vacancy on formation ability and mechanical properties of carbon-deficient high-entropy (TiVNbMoW)C4.375 were investigated. Intriguingly, although the starting binary carbides have different crystal structures and carbon stoichiometry, the as-prepared high-entropy material showed a rock-salt structure with a relatively high density (98.1%) and good mechanical properties with hardness of 19.4±0.4 GPa and fracture toughness (KIC) of 4.02 MPa·m1/2. More importantly, the high-entropy (TiVNbMoW)C4.375 exhibited low coefficient of friction (COF) at room temperature (RT) and 800 ℃. Wear rate (W) gradually increased with the temperature rising, which were attributed to the formation of low-hardness oxidation films at high temperatures to aggravate wear. At 800 ℃, lubricating films formed from sufficient oxidation products of V2O5 and MoO3 effectively improved tribological behavior of ...