Atomic Crack Tips in Covalent Crystal
Crack tip geometries in covalent crystals were studied by high resolution (HR) TEM. The materials used in the study were SiC, Si crystals and 15R-sialon grain. Cracks were introduced by Vickers indentation in SiC and Si. In 15R-sialon, crack was naturally introduced. It was found that the crack tips were atomically sharp and there was no macroscopic yielding zone. The results of TEM observation are summarized here.
KeywordsDislocation Segment Sharp Crack Vickers Indentation Covalent Crystal Cleavage Crack Propagation
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