Fracture and property relationships in the double diboride ceramic composites by spark plasma sintering of TiB 2 and NbB 2

Dmytro Demirskyi, Ievgen Solodkyi, Toshiyuki Nishimura, Oleg O. Vasylkiv

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Bulk titanium diboride–niobium diboride ceramic composites were consolidated by spark plasma sintering (SPS) at 1950°C. SPS resulted in dense specimens with a density exceeding 98% of the theoretical density and a multimodal grain size ranging from 1 to 10 µm. During the SPS consolidation, the pressure was applied and released at 1950 and 1250°C, respectively. This allowed obtaining a two-phase composite consisting of TiB 2 and NbB 2 . For these ceramics composites, we evaluated the flexural strength and fracture toughness and room and elevated temperatures. Room-temperature strength of thus produced bulks was between 300 and 330 MPa, at 1200°C or 1600°C an increase in strength up to 400 MPa was observed. Microstructure after flexure at elevated temperatures revealed the appearance of the needle-shape subgrains of NbB 2 , an evidence for ongoing plastic deformation. TiB 2 –NbB 2 composites had elastic loading stress curves at 1600°C, and at 1800°C fractured in the plastic manner, and strength was ranged from 300 to 450 MPa. These data were compared with a specimen where a (Ti,Nb)B 2 solid solution was formed during SPS to explain the behavior of TiB 2 –NbB 2 ceramic composites at elevated temperatures.

Original languageEnglish
Pages (from-to)4259-4271
Number of pages13
JournalJournal of the American Ceramic Society
Volume102
Issue number7
DOIs
Publication statusPublished - 2019 Jul

Keywords

  • composite
  • elevated temperature strength
  • flexural strength
  • niobium diboride
  • titanium diboride

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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