The sinter forging behavior of α-Al2O3 seeded and unseeded nanocrystalline (θ-Al2O3 was investigated as a function of temperature, stress, and strain rate. Seeded samples exhibited the highest degree of plastic deformation during the θ- to α-Al2O3 phase transformation. As a result, microstructure control, increased densification, and a higher degree of transformation were obtained. A uniform microstructure of 150 nm α-Al2O3 grains developed, reaching 57% relative density after sintering 1.5 wt% α-Al2O3 seeded samples for 30 min at 1060°C. When sinter forged at 0.25 mm/min to 63 MPa and 1060°C for 30 min large deformations during the phase transformation increased the relative density to 74%. When the stress was increased to 235 MPa (1060°C, 30 min), 99.7% dense α-Al2O3 with a grain size of 230 nm was obtained. By increasing the sinter forging temperature to 1150°C, 99.5% relative density was achieved at 190 MPa for 30 min.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - Jan 1 1996|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry