Abstract
Addition of 5 and 10 wt.% Si3N4 whiskers to Si3N4 hot-pressed with 3% MgO resulted in an increase of toughness perpendicular to the hot-pressed direction of 25% (8.8 MPa.m1/2) and 14% (8.0 MPa.m1/2), respectively, compared to the monolithic material (7.0 MPa.m1/2). However, the same whisker additions to Si3N4 hot-pressed with 6% Y2O3 sintering aid, decreased the toughness of the composite by 18% (6.7 MPa.m1/2) and 10% (7.4 MPa.m1/2), respectively, compared to the monolithic material (8.2 MPa.m1/2). Despite the above differences in toughness, a Weibull modulus of 12 was found for all materials, irrespective of the amount of whiskers and type of sintering aids. Grain size variation did not uniquely explain the above differences in fracture toughness. A crack deflection mechanism predominated and could be correlated with the low value of Weibull modulus.
Original language | English (US) |
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Pages (from-to) | 211-218 |
Number of pages | 8 |
Journal | Ceramic Engineering and Science Proceedings |
Volume | 18 |
Issue number | 3 A |
State | Published - 1997 |
Event | Proceedings of the 1997 21st Annual Conference on Composites, Advanced Ceramics, Materials, and Structures-B - Cocoa, FL, USA Duration: Jan 12 1997 → Jan 16 1997 |
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry