Deformation microstructure of high-quality synthetic diamond crystal subjected to Knoop indentation

Abstract

The deformation microstructures of high-quality synthetic type IIa diamond crystal around a Knoop indentation formed at room temperature were investigated. The atomic force microscopy observation showed that there are smooth deformation areas without cracks or fractures around the indentation. In addition, many dislocation lines which lie on {111} planes and have Burgers vectors in ⟨110⟩ directions were observed beneath the Knoop indentation in transmission electron microscopy investigations. These results reveal that plastic deformation in diamond is possible beneath Knoop indentations even at room temperature, and that the deformation is mainly ascribed to {111}⟨110⟩ slip systems.