Reactive consolidation and high-temperature strength of HfB2–SiB6

D. Demirskyi*, T. Nishimura, T. S. Suzuki, K. Yoshimi, O. Vasylkiv

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

During the spark plasma sintering at 1900 °C, SiB6 decomposes into cubic silicon carbide and boron carbide, owing to the reducing environment of the furnace. For the HfB2-SiB6 ceramic improvement in hardness (24.5 ± 0.7 GPa) was attributed to the formation of the B12(C,Si,B)3. Fracture toughness by indentation (6.8 ± 2.4 MPa·m1/2), single-edge notched bend specimens (4.6 ± 0.4 MPa·m1/2) and room-temperature strength (513 ± 21 MPa) of the HfB2–SiB6 composite produced by spark plasma sintering was higher or on the same level as the HfB2–SiC ceramics. The high-temperature flexural strength tests suggested that the strength would decrease monotonically with an increase in temperature. At or below 1600 °C, only a linear stress-strain response was observed, and resulted into a mean strength of ~320 MPa. During the tests at 1800 °C, we observed a nonlinear deformation indicating ongoing plastic deformation which led to a strength decrease down to 230 ± 30 MPa.

Original languageEnglish
Pages (from-to)4783-4792
Number of pages10
JournalJournal of the European Ceramic Society
Volume42
Issue number12
DOIs
Publication statusPublished - 2022 Sep
Externally publishedYes

Keywords

  • Flexural strength
  • Hafnium diboride
  • High-temperature materials
  • Reactive decomposition
  • Silicon hexaboride

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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