Creep behavior in SiC-whisker reinforced silicon nitride composite

摘要

Tensile and flexural creep tests of 20 vol.% SiC whiskers reinforced Si sub 3 N sub 4 composite processed by gas pressure sintering have been carried out in air in the temperature range of 1000-1300 deg C. The stress exponent for flexural creep is 16 at 1000 deg C. However, at 1200 and 1250 deg C the stress exponents for both tensile and fleural creep vary with increasing stress. In the low stress region, the activation energy for creep is 1000 kJ /mol. In the high stress region, it is 680 kJ/mol. The different creep mechanisms dominate in the low and high stress regions, respectively.