Grain Growth and Fracture Toughness of Fine-Grained Silicon Carbide Ceramics

Fine-grained silicon carbide ceramics with an average grain size of 0.11 mu m were liquid-phase sintered from fine beta -SiC powder by hot pressing. The hot-pressed materials were subsequently annealed to enhance grain growth. The diameters and aspect ratios of grains in the hot-pressed and annealed...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 1995-11, Vol.78 (11), p.3145-3148
Main Authors: Kim, Young-Wook, Mitomo, Mamoru, Hirotsuru, Hideki
Format: Article
Language:English
Subjects:
Applied sciences
Building materials. Ceramics. Glasses
Ceramic industries
Chemical industry and chemicals
Exact sciences and technology
Miscellaneous
Technical ceramics
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Summary:Fine-grained silicon carbide ceramics with an average grain size of 0.11 mu m were liquid-phase sintered from fine beta -SiC powder by hot pressing. The hot-pressed materials were subsequently annealed to enhance grain growth. The diameters and aspect ratios of grains in the hot-pressed and annealed materials were measured on polished and etched surfaces. The bimodal grain size distribution in annealed materials was obtained at 1850 deg C without appreciable phase transformation. The average diameter and average aspect ratio increased with annealing time. The fracture toughness of a fine-grained silicon carbide ceramic determined by the Vickers indentation method was 1.9 MPam exp 1/2 . The fracture toughness increased to 6.1 MPam exp 1/2 after grain growth by annealing at 1850 deg C for 12 h. Higher fracture toughness of annealed materials is due to bridging by elongated grains as evidenced by R-curve-like behavior.
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1151-2916.1995.tb09100.x