Mechanical Properties of Borothermally Synthesized Zirconium Diboride at Elevated Temperatures
The mechanical properties of a nominally phase pure ZrB2 ceramic were measured up to 2300°C in an argon atmosphere. ZrB2 was hot pressed at 2000°C utilizing borothermally synthesized powder from high purity ZrO2 and B raw materials. The relative density of the ceramics was about 95% with an average ZrB2 grain size of 8.8 µm. The room temperature flexural strength was 447 MPa, with strength decreasing to 196 MPa at 1800°C, and then increasing to 360 MPa at 2300°C. The strength up to 1800°C was likely controlled by a combination of effects: surface damage from oxidation of the specimens, stress relaxation, and decreases in the elastic modulus. The strength above 1800°C was controlled by flaws in the range consistent with sizes of the maximum ZrB2 grain size and the largest pores. Fracture toughness was 2.3 MPa·m1/2 at room temperature, increasing to 3.1 MPa·m1/2 at 2200°C. The use of higher purity starting materials improved the mechanical behavior in the ultra-high temperature regime compared to previous studies.
A. C. Murchie et al., "Mechanical Properties of Borothermally Synthesized Zirconium Diboride at Elevated Temperatures," International Journal of Applied Ceramic Technology, vol. 18, no. 4, pp. 1235-1243, Wiley, Jul 2021.
The definitive version is available at https://doi.org/10.1111/ijac.13755
Materials Science and Engineering
Keywords and Phrases
Borides; Hot Pressing; Mechanical Properties
International Standard Serial Number (ISSN)
Article - Journal
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01 Jul 2021