High-entropy monoborides: Towards superhard materials

SCRIPTA MATERIALIA

卷:189

Article

Qin, Mingde¹  Yan, Qizhang¹  Wang, Haoren¹  Hu, Chongze¹  Vecchio, Kenneth S.¹  Luo, Jian¹ 

[1] Univ Calif San Diego, Dept NanoEngn, Program Mat Sci & Engn, La Jolla, CA 92093 USA

关键词: High-entropy ceramics;    High-entropy monoborides;    Reactive sintering;    Vickers hardness;    Superhard materials;   

DOI  :  10.1016/j.scriptamat.2020.08.018

来源: Elsevier

【 摘 要 】

Single-phase high-entropy monoborides (HEMBs) of the CrB prototype structure have been synthesized for the first time. Reactive spark plasma sintering of ball milled mixtures of elemental precursor powders produced bulk (V0.2Cr0.2Nb0.2Mo0.2Ta0.2)B, (V0.2Cr0.2Nb0.2Mo0.2W0.2)B, and (V0.2Cr0.2Nb0.2Ta0.2W0.2)B HEMS specimens of similar to 98.3-99.5% relative densities. Vickers hardness was measured to be similar to 22-26 GPa at an indentation load of 9.8 N and similar to 32-37 GPa at 0.98 N. In particular, the load-dependent hardness of (V0.2Cr0.2Nb0.2Mo0.2W0.2)B is higher than those of ternary (Ta0.5W0.5)B (already considered as superhard) and hardest reported high-entropy metal diborides, and on a par with the classical superhard boride WB4. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

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