Kinetics and Mechanisms of High-Temperature Creep in Silicon Carbide: I, Reaction-Bonded

The kinetic characteristics and the controlling mechanism of steady-state creep were determined for NC–430 reaction-bonded silicon carbide which was subjected to high temperatures (1848 to 1923 K) and constant compressive stresses (110 to 220 MN/m2). Both as-received and as-crept materials were studied extensively by transmission electron‘microscopy as one means of determining the controlling creep mechanism. Small variations in sample density resulted in large variations in the creep rate. The stress exponent, n in the relation εασn, was found to be 5.7 and the creep activation energy 711 ± 20 kJ/mol. The controlling creep mechanism was determined to be dislocation glide/climb controlled by climb.