Deformation-resistant Ta0.2Hf0.8C solid-solution ceramic with superior flexural strength at 2000°C

Dmytro Demirskyi*, Hanna Borodianska, Toshiyuki Nishimura, Tohru S. Suzuki, Kyosuke Yoshimi, Oleg Vasylkiv*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


In this study, we explored the consolidation, solid-solution formation and high-temperature properties of tantalum hafnium carbide with the 1 TaC:4 HfC ratio, that is, Ta0.2Hf0.8C. Tantalum hafnium carbide bulks can be consolidated using spark-plasma sintering only at temperatures exceeding 2200°C. The bulks prepared using a 40-min dwell at 2200°C had the lattice parameter a = 4.571(9) Å. Based on the three-point flexural tests, it was observed that the toughness and strength of Ta0.2Hf0.8C remained high at 2000°C (3.4 ± 0.4 MPa m1/2, 500 ± 20 MPa). At 2000°C, majority of carbides show a plastic behavior, but the strain-stress curves of the SPSed Ta0.2Hf0.8C ceramic were linear. Using the shrinkage rate data during the SPS and the strain-stress data from the high-temperature flexure, we estimated the activation energies for the densification and flexure as 820 ± 20 kJ/mol and 1180 ± 120 kJ/mol, respectively.

Original languageEnglish
Pages (from-to)512-524
Number of pages13
JournalJournal of the American Ceramic Society
Issue number1
Publication statusPublished - 2022 Jan
Externally publishedYes


  • flexural strength
  • spark plasma sintering
  • tantalum hafnium carbide
  • ultra-high-temperature ceramics

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry


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