Mechanical Properties and Grain Orientation Evolution of Zirconium Diboride-Zirconium Carbide Ceramics
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 for nominally pure ZrB2 to ~4.3MPa√m due to residual thermal stresses. The toughness was comparable with ZrB2 up to 1600 °C, but increased to 4.6MPa√m 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  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.
A. D'Angio et al., "Mechanical Properties and Grain Orientation Evolution of Zirconium Diboride-Zirconium Carbide Ceramics," Journal of the European Ceramic Society, vol. 38, no. 2, pp. 391-402, Elsevier Ltd, Feb 2018.
The definitive version is available at https://doi.org/10.1016/j.jeurceramsoc.2017.09.013
Materials Science and Engineering
Keywords and Phrases
Borides; Electron Backscattering Diffraction (EBSD); High-Temperature Mechanical Properties; Particulate Reinforced Composites; Ultra-High Temperature Ceramics (UHTC)
International Standard Serial Number (ISSN)
Article - Journal
© 2018 Elsevier Ltd, All rights reserved.