Superhard high-entropy dodecaboride with high electrical conductivity. (November 2022)

• Record Type: Journal Article
• Authors: Zheng, Xingwei; Cui, Jian; Gu, Chao; Bao, Weichao; Zhou, Xuefeng; Liu, Ji-Xuan; Zhang, Guo-Jun; Zhang, Wenqing; Zhao, Yusheng; Wang, Shanmin; Liang, Yongcheng
• Is Part Of: Scripta materialia. Number 220(2022)
• Publication Date: 2022-11
• Subjects: High-entropy dodecaborides -- Electrical conductivity -- Hardness -- Design -- Synthesis; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2022.114938
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: Methods used to enhance the hardness of a material often render a noticeable deterioration of electrical conductivity so that a tradeoff must be made between conductivity and hardness. Here, we report a counterintuitive strategy for the design of superhard materials with superior electrical conductivity. We subsequently synthesized a high-entropy rare-earth dodecaboride that is a highly disordered homogeneous crystalline single phase with the UB12 -type structure. This material exhibits a sufficient enhancement of hardness (∼43.1 GPa under a load of 0.49 N) over its constituent binary dodecaborides, while possessing a high electrical conductivity (∼1.96 × 10 7 S/m) comparable to that of pure metals. A high content of lightweight boron enables a substantial reduction in its density compared with other hard metal compounds. The extraordinary metal-like conductivity, together with high hardness and low density, makes it find promising applications as body armors and hard conductors under extreme conditions. Graphical abstract: Image, graphical abstract