Mechanical properties and grain orientation evolution of zirconium diboride-zirconium carbide ceramics. Issue 2 (February 2018)

• Record Type: Journal Article
• Authors: D'Angio', A.; Zou, J.; Binner, J.; Ma, Hai-Bin; Hilmas, G.E.; Fahrenholtz, W.G.
• Is Part Of: Journal of the European Ceramic Society. Volume 38:Issue 2(2018)
• Page Start: 391
• Page End: 402
• Publication Date: 2018-02
• Subjects: Ultra-high temperature ceramics (UHTC) -- Particulate reinforced composites -- Borides -- High-temperature mechanical properties -- Electron backscattering diffraction (EBSD); Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2017.09.013
• Languages: English
• ISSNs: 0955-2219

Abstract

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 .5 MPa m for nominally pure ZrB2 to ∼ 4 .3 MPa m due to residual thermal stresses. The toughness was comparable with ZrB2 up to 1600 °C, but increased to 4 .6 MPa 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 [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.