Mechanical behaviours of hot-pressed rare-earth oxide (RE = Y and La)-doped TaB2-SiC composites

Shuqi Guo; Gaku Okuma; Kimiyoshi Naito; Hideki Kakisawa

doi:10.1016/j.jeurceramsoc.2023.10.057

Article Mechanical behaviours of hot-pressed rare-earth oxide (RE = Y and La)-doped TaB2-SiC composites

Shuqi Guo (National Institute for Materials Science) ; Gaku Okuma (National Institute for Materials Science) ; Kimiyoshi Naito (National Institute for Materials Science) ; Hideki Kakisawa (National Institute for Materials Science)

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Shuqi Guo, Gaku Okuma, Kimiyoshi Naito, Hideki Kakisawa. Mechanical behaviours of hot-pressed rare-earth oxide (RE = Y and La)-doped TaB2-SiC composites. Journal of the European Ceramic Society. 2023, 44 (3), 1445-1457. https://doi.org/10.1016/j.jeurceramsoc.2023.10.057

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In this study, TaB2-20 vol% SiC composites with and without rare-earth oxides (RE2O3, RE = Y and La) were fabricated via hot pressing at or above 1800°C. 3 vol% RE2O3 additions improved the sinterability of TaB2-SiC composite and resulted in a finer microstructure in addition to the crystalline RE2Si2O7 grain-boundary phase. The shear and Young’s moduli as well as hardness of the composites decreased with RE2O3 additives. Conversely, the fracture toughness of the composites increased with RE2O3 additives and the toughening effect was better for La2O3 than for Y2O3. On the other hand, the additions of RE2O3 substantially enhanced the flexural strength and the strengthening effect was significantly stronger for Y2O3 than for La2O3, the strengthening was ineffective at or above 1400°C, however. Additionally, the temperature dependence of strengths varied with and without RE2O3 additions, as a result of the difference in the chemistry of the intergranular phases.

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