Ultra-high temperature flexure and strain driven amorphization in polycrystalline boron carbide bulks

D. Demirskyi*, H. Sepehri-Amin, T. S. Suzuki, K. Yoshimi, O. Vasylkiv

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The temperature dependence of the flexural strength of sintered boron carbide was studied. At temperatures above 2000 °C, B4C showed an ultrahigh flexural strength exceeding 1 GPa which was accompanied by a change in the deformation mechanism from brittle fracture to plastic deformation. Scanning transmission electron microscopy (STEM) observations revealed that the amorphization can be of microstructural origin for the observed plasticity in B4C at temperatures above 2000 °C and a strain rate of 3•10−3 s−1. The amorphization occurs inside of the severely deformed grains. Flexural tests below 2000 °C provided evidence for the formation of stacking faults or dislocations, which are ordinary defects after the flexural tests. The results at 2000 °C suggest that the magnitude of the tensile stresses imposed on the B4C grains during deformation in flexure and the total strain transferred to a ceramic during the deformation process play the dominant role in the crystalline-amorphous transformation.

Original languageEnglish
Article number114487
JournalScripta Materialia
Volume210
DOIs
Publication statusPublished - 2022 Mar 15
Externally publishedYes

Keywords

  • Boron carbide
  • Crystal defects
  • High-temperature deformation
  • Transmission electron microscopy (TEM)

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys

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