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New deformation resistance ceramics can be used for engine and vehicle protection, aerospace components, plasma-facing ceramic parts, gas turbine operation, and other applications that require a balance of strength, toughness, and hardness.
I will discuss the resistance to ultrahigh-temperature deformation of boron carbide, Ta0.2Hf0.8C, TiB2-B4C, Zr-Ta multi-boride, Ta monoboride, and diboride. The idea behind the deformation-resistant ceramics (DRC) concept is that during densification, a novel or solid solution phase is formed that is more difficult to densify or deform. As a result, forming some of these phases is advisable only at elevated temperatures in situ during the densification process. In our experience, once the DRC phase is formed, it should require a temperature higher or equal to that of densification temperature to activate mass transport, thus yielding activation of plasticity at/above 2000°C.
The mechanism of ultra-high temperature flexure & strain-driven amorphization in polycrystalline B4C has been analyzed. With RT to 1800 °C mean strength of 650 MPa, B4C exhibits ultrahigh flexural strength far exceeding 1000 MPa, accompanied by a change in the deformation mechanism from brittle fracture to plastic deformation at 2000 °C. Depending on the loading rate, B4C ceramic showed 1000 - 8400 MPa strength with a plastic stress-strain curve. Even deformation in an elastic manner at 25 mm/min resulted in a strength of 675 MPa, confirming its deformation resistivity.

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Keyword: Deformation resistivity, carbides, borides, UHTC

Conference: The 37th Fall Meeting of The Ceramic Society of Japan (日本セラミックス協会 第37回秋季シンポジウム) (2024-09-10 - 2024-09-12)

Funding:

• NIMS, JSPS (KAKENHI 24K08035) KCB101 (非晶質相形成による超高温セラミックスの高)
• NIMS AB3080 (多結晶光学材料 Research toward Innovative Optical Materials)

Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4982

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Updated at: 2025-04-10 21:48:44 +0900

Published on MDR: 2024-11-21 16:35:52 +0900