Journal ArticleDOI
Nanomechanical properties of Au (111), (001), and (110) surfaces
J. D. Kiely,Jack E. Houston +1 more
TLDR
In this article, the authors quantitatively investigated the mechanical properties for the (111), (001), and (110) surfaces of Au single crystals and quantified the yield point of the three crystal orientations by measuring the stress at which initial plastic deformation occurs.Abstract:
Using the interfacial force microscope in an indentation mode, we have quantitatively investigated the mechanical properties for the (111), (001), and (110) surfaces of Au single crystals. Nanoscale indentations of wide, atomically flat terraces provide a measure of the nanomechanical properties of Au in the absence of bulk and surface defects. The elastic indentation modulus for the (111) surface was found to be 36% greater than for the (001) and 3% greater than for the (110) surfaces. These results are compared to earlier theoretical predictions of the effect of anisotropy on indentation based on continuum mechanics and atomistic simulations. Additionally, we have quantified the yield point of the three crystal orientations by measuring the stress at which initial plastic deformation occurs. By resolving the applied stresses on {111} slip planes, we have estimated maximum shear stresses at the yield point. For each orientation, plastic deformation occurred when the maximum resolved shear stress reached approximately 1.8 GPa on all {111} planes that appeared to contribute to deformation. Based on this estimate, we propose that the critical resolved shear stress for plastic indentation of Au is 1.8 GPa and that the yield criterion is that this stress be attained on all {111} slip planes noncoplanar with the surface.read more
Citations
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Journal ArticleDOI
Dislocation nucleation and defect structure during surface indentation
TL;DR: In this paper, an atomistic imaging of dislocation nucleation during displacement controlled indentation on a passivated surface is presented, where defects are located and imaged by local deviations from centrosymmetry.
Journal ArticleDOI
Mechanical behavior of nanocrystalline metals and alloys
TL;DR: In this article, the authors present an overview of the mechanical properties of nanocrystalline metals and alloys with the objective of assessing recent advances in the experimental and computational studies of deformation, damage evolution, fracture and fatigue, and highlighting opportunities for further research.
Journal ArticleDOI
Mechanical properties of ultrahigh-strength gold nanowires
TL;DR: It is found that for Au nanowires, Young's modulus is essentially independent of diameter, whereas the yield strength is largest for the smallest diameter wires, with strengths up to 100 times that of bulk materials, and substantially larger than that reported for bulk nanocrystalline metals.
Journal ArticleDOI
Nanoindentation studies of materials
TL;DR: Nanoindentation has become a commonplace tool for the measurement of mechanical properties at small scales, but may have even greater importance as a technique for experimental studies of fundamental materials physics as discussed by the authors.
Journal ArticleDOI
The breakdown of continuum models for mechanical contacts
Binquan Luan,Mark O. Robbins +1 more
TL;DR: This work uses molecular simulations to test the limits of contact mechanics under ideal conditions and indicates that atomic discreteness within the bulk of the solids does not have a significant effect, but that the atomic-scale surface roughness that is always produced by discrete atoms leads to dramatic deviations from continuum theory.
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