High-Temperature Failure Mechanisms of Hot-Pressed Si3N4 and Si3N4/Si3N4-Whisker-Reinforced Composites

The high‐temperature flexural strength of hot‐pressed silicon nitride (Si3N4) and Si3N4‐whisker‐reinforced Si3N4‐matrix composites has been measured at a crosshead speed of 1.27 mm/min and temperatures up to 1400°C in a nitrogen atmosphere. Load–displacement curves for whisker‐reinforced composites...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 1993-05, Vol.76 (5), p.1349-1353
Main Authors: Chu, Cha-Yang, Singh, Jitendra P., Routbort, Jules L.
Format: Article
Language:English
Subjects:
Applied sciences
Building materials. Ceramics. Glasses
Ceramic industries
Chemical industry and chemicals
Exact sciences and technology
Structural ceramics
Technical ceramics
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Summary:The high‐temperature flexural strength of hot‐pressed silicon nitride (Si3N4) and Si3N4‐whisker‐reinforced Si3N4‐matrix composites has been measured at a crosshead speed of 1.27 mm/min and temperatures up to 1400°C in a nitrogen atmosphere. Load–displacement curves for whisker‐reinforced composites showed nonelastic fracture behavior at 1400°C. In contrast, such behavior was not observed for monolithic Si3N4. Microstructures of both materials have been examined by scanning and transmission electron microscopy. The results indicate that grain‐boundary sliding could be responsible for strength degradation in both monolithic Si3N4 and its whisker composites. The origin of the nonelastic failure behavior of Si3N4‐whisker composite at 1400°C was not positively identified but several possibilities are discussed.
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1151-2916.1993.tb03764.x