Stress-induced phase transitions in diamond

Abstract

A phase transformation in diamond into an intermediate carbon phase (ICP) was revealed in regions of maximal shear stress of diamond anvils. The transition was stimulated by additional stresses supplied to the compressed anvils with torque by a rotation of the anvil around the anvil's axis; maximal shear stress approached 55 GPa during the rotation. Creation of an ICP is considered as a mechanism of the stress-induced stability loss of the diamond structure. The characteristic Raman bands of ICP near 250, 500, 650–850 and 1050–1390 cm⁻¹ were observed in the failure regions.

Keywords:

• diamond crystal
• metastable phases
• diamond-like carbon
• mechanical properties

Acknowledgements

The author thanks Prof. V. Blank for fruitful discussion.