Superhard High-Entropy AlB₂-Type Diboride Ceramics

Author

Lun Feng
Frédéric Monteverde
William Fahrenholtz, Missouri University of Science and TechnologyFollow
Greg Hilmas, Missouri University of Science and TechnologyFollow

Abstract

Hardness was measured for six different nominally pure and single-phase high-entropy diboride ceramics with the AlB₂ structure that were produced by a two-step process. Most of the ceramics had relative densities greater than 99.5%. Vickers hardness average values ranged from 21.0 GPa to 25.4 GPa at a load of 9.81 N, while values increased to the range of 33.1 GPa to 48.3 GPa at a load of 0.49 N. Among the compositions, the highest hardness values at a load of 0.49 N were 48.3 ± 2.3 GPa for (Cr_0.2Hf_0.2Ta_0.2Ti_0.2Zr_0.2)B₂ and 45.8 ± 5.3 GPa for (Hf_0.2Ta_0.2Ti_0.2W_0.2Z_r0.2)B₂, both of which are high enough to be considered superhard. The present study demonstrated that high-entropy diboride ceramics are a new class of superhard materials.

Recommended Citation

L. Feng et al., "Superhard High-Entropy AlB₂-Type Diboride Ceramics," Scripta Materialia, vol. 199, Elsevier, Jul 2021.

The definitive version is available at https://doi.org/10.1016/j.scriptamat.2021.113855

Department(s)

Materials Science and Engineering

Comments

National Science Foundation, Grant CMMI-1902069

Keywords and Phrases

High-Entropy Borides; High-Entropy Ceramics; Superhard Materials; Vickers Hardness

International Standard Serial Number (ISSN)

1359-6462

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2021 Acta Materialia, All rights reserved.

Publication Date

01 Jul 2021