High-temperature strength of boron carbide with Pt grain-boundary framework in situ synthesized during spark plasma sintering

O. Vasylkiv, D. Demirskyi, H. Borodianska, A. Kuncser, P. Badica

Research output: Contribution to journalArticle

Abstract

Grain boundaries, twins, and defects are considered to influence the thermomechanical behavior of any covalent ceramic, as a result, monolithic B4C samples show different curve shapes of bending strength vs temperature and the present theoretical models fail to fit them over the entire temperature range. To overcome these issues, we fabricated a novel high-density boron carbide and evaluated its high-temperature bending strength. The as-obtained ceramic is composed of boron carbide grains and a fine grain-boundary metal Pt framework. The material shows a decreased strength, which is due to a non-linear increase in the volume expansion coefficient of the B4C. Recovery in strength above 1000 °C is due to the presence of twins, their growth and rearrangements. We consider twins rearrangements are the pieces of evidence for a novel ‘micro’ mechanism of high-temperature stress accommodation for the boron carbide bulks.

Original languageEnglish
Pages (from-to)9136-9144
Number of pages9
JournalCeramics International
Volume46
Issue number7
DOIs
Publication statusPublished - 2020 May

Keywords

  • Asymmetric twins
  • Bending strength
  • Boron carbide
  • Modified grain boundaries
  • Pt framework
  • Spark plasma sintering

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

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