Abstract

Dense, dual phase (Hf,Mo,Ti,W,Zr)B2–(Hf,Mo,Ti,W,Zr)C ceramics were synthesized with varying contents of Mo and W. The final (Hf0.317Mo0.025Ti0.317W0.025Zr0.317)C–(Hf0.317Mo0.025Ti0.317W0.025Zr0.317)B2 was a nominally pure, dual phase ceramic, while compositions with higher amounts of Mo and W contained multiple phases. The final microstructures had submicron grains due to pinning effects. Vickers hardness values were up to 48.6 ± 2.2 GPa for an applied load of 0.49 N for the ceramic with optimized composition and densification. The solubility limits for Mo and W into the (Hf,Mo,Ti,W,Zr)B2–(Hf,Mo,Ti,W,Zr)C ceramics were mitigated by decreasing their contents to 2.5 at% each, which produced a nominally pure dual phase ceramic that could be densified by spark plasma sintering or hot pressing. A synergistic hardening effect was observed for optimized ceramic with 5 at% of Mo and W, whereby it had a higher hardness than individual high entropy carbide and high entropy boride phases containing the same transition metals.

Department(s)

Materials Science and Engineering

Comments

Office of Naval Research, Grant N00014-21-1-2515

Keywords and Phrases

Dual-phase ceramics; Hardness; Spark plasma sintering; Ultrahigh temperature ceramics

International Standard Serial Number (ISSN)

1873-619X; 0955-2219

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Elsevier, All rights reserved.

Publication Date

01 Nov 2024

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