Superplastic behavior of liquid-phase sintered beta-SiC prepared with oxynitride glasses in an N-2 atmosphere

The superplastic behavior of liquid-phase sintered beta -SiC with oxynitrid e glasses was compared in compression and tension tests at 1973-2048 K in a n N-2 atmosphere. Strain hardening was observed under all experimental cond itions. Stress exponents in the compression tests of SiC with different add itives were about 2 in the temperature ranging from 1973 to 2023 K. Amorpho us phases were observed at the grain boundaries and at multi-grain junction s in the as-sintered materials. Superplastic behavior was greatly influence d by grain growth, vaporization of grain-boundary phase and formation of cr ystalline phase during tensile deformation. (C) 2001 Elsevier Science Ltd, All rights reserved.