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Mechanical properties of borothermally synthesized zirconium diboride at elevated temperatures
Author(s) -
Murchie Alec C.,
Watts Jeremy L.,
Fahrenholtz William G.,
Hilmas Gregory E.
Publication year - 2021
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/ijac.13755
Subject(s) - materials science , flexural strength , zirconium diboride , fracture toughness , composite material , ceramic , grain size , relative density , zirconium , atmospheric temperature range , microstructure , metallurgy , physics , meteorology
The mechanical properties of a nominally phase pure ZrB 2 ceramic were measured up to 2300°C in an argon atmosphere. ZrB 2 was hot pressed at 2000°C utilizing borothermally synthesized powder from high purity ZrO 2 and B raw materials. The relative density of the ceramics was about 95% with an average ZrB 2 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 ZrB 2 grain size and the largest pores. Fracture toughness was 2.3 MPa·m 1/2 at room temperature, increasing to 3.1 MPa·m 1/2 at 2200°C. The use of higher purity starting materials improved the mechanical behavior in the ultra‐high temperature regime compared to previous studies.