Probing the local creep mechanisms of SiC/SiC ceramic matrix composites with high-temperature nanoindentation

Here, we probed the local creep response of SiC/SiC ceramic matrix composites via high-temperature indentation to examine the contributions of heterogeneous microstructure to creep. Indentations were conducted up to 800 degrees C on single and polycrystalline Si and SiC, reaction-bonded SiC, and the SiC/SiC composite, which indicated higher creep strain rates of polycrystalline materials yet uncovered comparably lower strain rates of the SiC/SiC composite. Indentation creep rate was observed to be highly dependent on contact stresses. An analytical creep model was presented based on a rule of mixtures approach to incorporate material heterogeneity of the SiC/SiC composite. A finite element model was applied to predict the indentation deformation zone, in which the composite constituents would jointly influence the creep response. The analytical model was then solved for temperatures up to 800 degrees C and exhibited good agreement with experimental measurements. Graphic abstract

Automated summary

The local creep response of SiC/SiC ceramic matrix composites was examined via high-temperature indentation to study the contributions of heterogeneous microstructure to creep. Different materials showed varying creep strain rates under indentation tests, with a developed analytical creep model based on a rule of mixtures approach to incorporate material heterogeneity of the SiC/SiC composite. The finite element model predicted the indentation deformation zone influenced by the composite constituents and showed good agreement with experimental measurements up to 800 degrees C.