Abstract
Effect of microstructure on the fracture toughness for Si3N4 ceramics were studied. The Si3N4 ceramics were fabricated by pressureless sintering using two kinds of Si3N4 powders (high purity powder: E10, and relatively low purity powder: 9S) as starting powders. Grain growth of β-silicon nitride was controlled by keeping time and sintering temperature. The fracture toughness was measured by indentation fracture (IF) method and single-edge-precracked-beam (SEPB) method. There was a discrepancy between the fracture toughness values obtained by these two methods. From this study it was found that the materials with more large elongated Si3N4 grains gave higher fracture toughness, R-curve behavior and large discrepancy. This was contributed to the effects of grain bridging, pull-out and deflection by large elongated Si3N4 grains. Comparing the specimens fabricated from the E10 and 9S powders, both reached high fracture toughness over 9 MPa·m1/2 by the SEPB method.
Original language | English |
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Pages (from-to) | 195-198 |
Number of pages | 4 |
Journal | Key Engineering Materials |
Volume | 161-163 |
Publication status | Published - 1999 Jan 1 |
Externally published | Yes |
Keywords
- Fracture Toughness
- Grain Growth
- Silicon Nitride
ASJC Scopus subject areas
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering