This article is cited in 4 papers

Mechanical properties, strength physics and plasticity

Nucleation of cracks near the free surface in deformed metallic nanomaterials with a bimodal structure

I. A. Ovid'ko^abc, A. G. Sheinerman<sup>abc

a</sup> Research Laboratory "Mechanics of New Nanomaterials", Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
^b Institute of Problems of Mechanical Engineering, Russian Academy of Sciences, St. Petersburg
^c Saint Petersburg State University

Abstract: A theoretical model that effectively describes the nucleation of cracks in stress fields of dislocation pile-ups near the free surface in metallic nanomaterials with a bimodal structure has been developed. The dependences of the critical shear stress $\tau_{c}$ (for the formation of a crack with an equilibrium length of 10 nm on a dislocation pile-up near the surface) on the size $d$ of a grain containing the dislocation pile-up have been calculated for copper with a bimodal structure. Theoretically, it has been found that the critical shear stress $\tau_{c}$ for the nucleation of a crack near the free surface in a nanomaterial with a bimodal structure is approximately 30% higher than that for the crack nucleation within the nanomaterial at a distance from the free surface.

Received: 24.11.2015

 English version: Physics of the Solid State, 2016, 58:6, 1179–1183

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