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Mechanical Properties and Deformation of Cubic Silicon Carbide Micropillars in Compression at Room Temperature

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Author to whom correspondence should be addressed. e-mail: cshin@kaeri.re.kr

Abstract

We performed microcompression tests on silicon carbide (SiC) pillars with diameters ranging from 4.7 down to 0.65 μm at room temperature. The SiC micropillars were fabricated from a polycrystalline 3C-SiC plate using lithography and plasma etching. The pillars exhibited elastic loading behavior until a catastrophic brittle fracture occurred. The compressive fracture strength was found to increase with a decrease in pillar diameter. This scale dependency can be attributed to the flaw sensitivity of brittle materials, and cracking seems to start at the grain boundaries. Ductile plasticity occurred in micropillars with a diameter of 0.65 μm. Cross-sectional transmission electron microscopy observation of the plastically deformed pillars showed that a slip occurred on the {111} planes. The critical resolved shear stress for a {111}<110> slip system was evaluated to be 4.9–7.3 GPa, which is consistent with the values obtained from numerical and theoretical studies in the literature.

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