Abstract
Ultrahigh temperature ceramic matrix composites (UHTCMCs) were fabricated from unidirectional prepreg tapes consisting of a matrix of ZrB2 with 5, 10, and 15 vol.% ZrSi2 additions and continuous polyacrylonitrile carbon fibers and were densified at 1600°C in a hot press. The relative matrix densities ranged from 88% to 93% with interlayer spacings of ∼72 µm and fiber volume fractions between 30% and 36%. Phenolic resin additions were utilized to react with ZrSi2 acting as a transient sintering aid to form ZrC and SiC phases. Elastic moduli of the UHTCMCs decreased with increasing temperature during 4-pt flexure testing. The elastic moduli values were 95–122 GPa at room temperature and ∼26 GPa for all three compositions at 1800°C. Strength increased as test temperature increased for each UHTCMC with varying rollover temperatures for each composition. Strength started decreasing above 1400°C for the 5 vol.% ZrSi2 composition, above 1600°C for the 10 vol.% ZrSi2 composition and did not decrease for the 15 vol.% ZrSi2 composition over the range of temperatures tested. The work of fracture increased from 0.3 to 1.9 kJ/m2 at room temperature to 18 to 20 kJ/m2 for each UHTCMC at 1800°C. All UHTCMCs displayed graceful failure beyond the initial fracture event.
Recommended Citation
J. Stacy et al., "Elevated Temperature Flexure Behavior of Continuous Carbon Fiber Reinforced ZrB2–ZrSi2 Ultrahigh Temperature Ceramic Matrix Composites," Journal of the American Ceramic Society, vol. 109, no. 1, article no. e70446, Wiley, Jan 2026.
The definitive version is available at https://doi.org/10.1111/jace.70446
Department(s)
Materials Science and Engineering
Publication Status
Full Access
Keywords and Phrases
high temperature flexure; UHTCMC; ZrB2
International Standard Serial Number (ISSN)
1551-2916; 0002-7820
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2026 Wiley, All rights reserved.
Publication Date
01 Jan 2026
