Mechanical properties and grain orientation evolution of zirconium diboride-zirconium carbide ceramics

Research output: Contribution to specialist publicationArticle

Authors

  • Andrea D'Angio'
  • Hai-Bin Ma
  • Gregory E. Hilmas
  • William G. Fahrenholtz

Colleges, School and Institutes

External organisations

  • Shanghai Institute of Ceramics, Chinese Academy of Science
  • Materials Science and Engineering Department, Missouri University of Science and Technology

Abstract

The effect of ZrC on the mechanical response of ZrB2 ceramics has been evaluated from room temperature to 2000°C. Zirconium diboride ceramics containing 10 vol% ZrC had higher strengths at all temperatures compared to previous reports for nominally pure ZrB2. The addition of ZrC also increased fracture toughness from 3.5MPa m(1/2) for nominally pure
ZrB2 to 4.3MPa m(1/2) due to residual thermal stresses. The toughness was comparable with ZrB2 up to 1600°C, but increased to 4.6MPa m(1/2) . at 1800°C and 2000°C. The increased toughness above 1600°C was attributed to plasticity in the ZrC at elevated temperatures. Electron back-scattered diffraction analysis showed strong orientation of the ZrC grains along the [001] direction in the tensile region of specimens tested at 2000°C, a phenomenon that has not been observed previously for fast fracture (crosshead displacement rate = 4.0 mm
min-1) in four point bending. It is believed that microstructural changes and plasticity at elevated temperature were the mechanisms behind the ultrafast reorientation of ZrC.

Details

Original languageEnglish
JournalJournal of the European Ceramic Society
Publication statusE-pub ahead of print - 12 Sep 2017

Keywords

  • ultra-high temperature ceramics (UHTC) , particulate reinforced composites , borides , high-temperature mechanical properties , electron backscattering diffraction (EBSD)