High-throughput screening of the static friction and ideal cleavage strength of solid interfaces

Michael Wolloch,Gabriele Losi,M. Clelia Righi,Mauro Ferrario

doi:10.1038/s41598-019-49907-2

Michael Wolloch, Gabriele Losi + Show 2 more

Open Access

https://doi.org/10.1038/s41598-019-49907-2

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Abstract

We present a comprehensive ab initio, high-throughput study of the frictional and cleavage strengths of interfaces of elemental crystals with different orientations. It is based on the detailed analysis of the adhesion energy as a function of lateral, γ(x, y), and perpendicular displacements, γ(z), with respect to the considered interface plane. We use the large amount of computed data to derive fundamental insight into the relation of the ideal strength of an interface plane with its adhesion. Moreover, the ratio between the frictional and cleavage strengths is provided as good indicator for the material failure mode – dislocation propagation versus crack nucleation. All raw and curated data are made available to be used as input parameters for continuum mechanic models, benchmarks, or further analysis.

Highlights

We present a comprehensive ab initio, high-throughput study of the frictional and cleavage strengths of interfaces of elemental crystals with different orientations
First we look at the potential energy surface (PES or γ-surface), which allows to derive several important characteristics of an interface
Radial basis functions are used for the interpolation between the computed data to obtain a smooth γ-surface, and the PES is shifted by subtracting the minimum energy, so that the maximal corrugation Δγ is sighted as the highest peak of the γ-surface

Summary

Introduction

We present a comprehensive ab initio, high-throughput study of the frictional and cleavage strengths of interfaces of elemental crystals with different orientations. The protocol is based on the calculation of the γ-surface, called generalized stacking fault energy or potential energy surface (PES), which describes the variation of the adhesion energy between two surfaces (modelled by two mating slabs within the same supercell) as a function of their relative lateral position This energy variation is the origin of frictional forces. E., its resistance to brittle fracture under tensile strain, from the derivative of the adhesion energy as a function of the surface separation While this protocol can be applied to obtain the ideal shear and cleavage strengths of generic interfaces, e.g., interfaces obtained by mating surfaces of different materials, or partially covered by adsorbates, here we focus on homogeneous interfaces formed by two equivalent surfaces. It has been shown that the generalized stacking fault energy differs by the affine strain energy in materials where the sliding of a layer is strongly coupled with the sliding of the adjacent layers, e.g., in materials with directional bonds[14]

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