Approaching the Limits of Strength: Measuring the Uniaxial Compressive Strength of Diamond at Small Scales

J. M. Wheeler; R. Raghavan; J. Wehrs; Y. Zhang; R. Erni; J. Michler

Nano Letters 16 (2016) 812-816

Diamond <100>– and <111>-oriented nanopillars were fabricated by focused ion beam (FIB) milling from synthetic single crystals and compressed using a larger diameter diamond punch. Uniaxial compressive failure was observed via fracture with a plateau in maximum stress of ∼0.25 TPa, the highest uniaxial strength yet measured. This corresponded to maximum shear stresses that converged toward 75 GPa or ∼ G/7 at small sizes, which are very close to the ultimate theoretical yield stress estimate of G/2π. (Figure Presented).