The creep behavior of Si3N4/SiC nanocomposites

Abstract

a In an investigation of the creep properties of silicon nitride/silicon carbide nanocomposites, the micro-nano type composites with nano-SiC at intragranular and inter-granular regions show behavior not much different from that of silicon-nitride monolith. The improvement of creep resistance is modest, up to about one order of magnitude decrease in steady-state creep rate. The creep rate parameters such as activation energy and stress exponent measured for this type of nanocomposite are within the range of those of silicon nitride. This evidence suggests that a special strengthening mechanism may not be necessary for this type of material. Nano-nanocomposites show remarkably lower creep rates, possibly pointing to a new creep mechanism such as solid-state diffusion.