Superplastic behavior of liquid-phase sintered β-SiC prepared with oxynitride glasses in an N2 atmosphere

The superplastic behavior of liquid-phase sintered β-SiC with oxynitride glasses was compared in compression and tension tests at 1973–2048 K in an N2 atmosphere. Strain hardening was observed under all experimental conditions. Stress exponents in the compression tests of SiC with different additives were about 2 in the temperature ranging from 1973 to 2023 K. Amorphous phases were observed at the grain boundaries and at multi-grain junctions in the as-sintered materials. Superplastic behavior was greatly influenced by grain growth, vaporization of grain-boundary phase and formation of crystalline phase during tensile deformation.