| Autor: |
Huang, Rong, Gu, Hui, Rixecker, Georg, Aldinger, Fritz, Scheu, Christina, Rühle, Manfred |
| Zdroj: |
International Journal of Materials Research: Zeitschrift fuer Metallkunde; January 2022, Vol. 96 Issue: 5 p496-502, 7p |
| Abstrakt: |
The microstructures of liquid-phase sintered SiC with AlN℃Y2O3additives are systematically investigated by using transmission electron microscopy and analytical electron microscopy. Pure α-SiC as starting powder leads to fine, equiaxied microstructure. Introduction of α-SiC seed crystals into β-SiC powder accelerates the β-to-α-SiC phase transformation through a solution-precipitation process and promotes anisotropic grain growth, which results in a plate-like microstructure. Core/rim structures were found in both cases as a result of AlN dissolution into the re-precipitated part of SiC grains. This changes the liquid composition during sintering and induces crystallization of Y10Al2Si3O18N4and Y2O3in the triple-pockets. Amorphous films were observed to wet both grain boundaries and two-phase interfaces. A low ratio of AlN to Y2O3in the sintering additive accelerates the devitrification of triple-pockets. Additional annealing can further devitrify the triple-pockets as well as the amorphous GB films, leading to a microstructure with potentially higher creep resistance. |
| Databáze: |
Supplemental Index |
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