Compressive deformation behavior of Al-doped β-SiC at elevated temperature

Compression tests were performed on Al-doped β-SiC fabricated by hot-pressing using pyrolyzed polycarbosilane at 2123-2223 K in He. An amorphous phase was clearly seen at the grain boundaries in as-sintered specimens. The stress exponents were from 1.1 to 1.4 in the temperature range 2123-2223 K. Strain hardening was observed under all experimental conditions. The phase transformation from β to α was not observed even after the compression tests. The amorphous phase at grain boundaries was vaporized from specimen surfaces during testing. The deformation behavior was influenced by the dynamic change of grain-boundary structure.