Rev.Adv.Mater.Sci.(RAMS)
No 2, Vol. 10, 2005, pages 156-160

THE NANOSCALE STRENGTH OF ULTRA NANO CRYSTALLINE DIAMOND

Nicola M. Pugno

Abstract

Aim of this paper is the estimation of the still unknown ultrananocrystalline diamond nanoscale strength. In spite of its measured strength at the microscale, of ∼4 GPa, for a hypothetical nanowire with specified geometry (10x10x100 nm3) we have deduced a tremendously higher tensile strength, of ∼23 GPa, as well as a bending strength of ∼30 GPa. A fractal exponent of ∼2.5 and a Weibull modulus of ∼10 are also derived. Such results are shown to be compatible with a theoretical estimation of the ideal strength, deduced as ∼52 GPa by applying Quantized Fracture Mechanics, assuming the fracture quantum coincident with a grain size of ∼3 nm. Doped materials are also treated.

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