Hostname: page-component-84b7d79bbc-g78kv Total loading time: 0 Render date: 2024-07-30T23:00:25.313Z Has data issue: false hasContentIssue false
  • English
  • Français

MD Simulations of Compression of Nanoscale Iron Pillars

Published online by Cambridge University Press:  28 October 2011

Con J. Healy  and
Graeme J. Ackland
Con J. Healy
Affiliation:
School of Physics and Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Mayfield Road, Edinburgh EH9 3JZ, UK
Graeme J. Ackland
Affiliation:
School of Physics and Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Mayfield Road, Edinburgh EH9 3JZ, UK
Get access

Abstract

It is now possible to create perfect crystal nanowires of many metals. The deformation of such objects requires a good understanding of the processes involved in plasticity at the nanoscale. Isotropic compression of such nanometre scale micropillars is a good model system to understand the plasticity. Here we investigate these phenomena using Molecular Dynamics (MD) simulations of nanometre scale single crystal BCC iron pillars in compression.

We find that pillars with large length to width ratio may buckle under high strain rates. The type of buckling behaviour depends sensitively on the boundary conditions used: periodic boundary conditions allow for rotation at top and bottom of the pillar, and result in an S shaped buckle, by contrast fixed boundaries enforce a C shape. Pillars with a length to width ratio closer to that used in experimental micropillar compression studies show deformation behaviour dominated by slip, in agreement with the experiments. For micropillars oriented along <100>, slip occurs on <110> planes and localized slip bands are formed. Pillars of this size experience higher stresses than bulk materials before yielding takes place. One might expect that this may be in part due to the lack of nucleation sites needed to induce slip. However, further simulations with possible dislocation sources: a shorter iron pillar containing a spherical grain boundary, and a similar pillar containing jagged edges did not show a decreased yield strength.

Keywords

simulationmetalmicrostructure
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1369: Symposium XX – Computational Studies of Phase Stability and Microstructure Evolution , 2011 , mrss11-1369-XX03-03
Copyright
Copyright © Materials Research Society 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1] Uchic, Michael D., Shade, Paul A., and Dimiduk, Dennis M., Plasticity of Micrometer- Scale Single Crystals in Compression in The Annual Review of Materials Research , 39 (2009).Google Scholar
[2] Li, Xiaoyan and Yang, Wei, Size Dependence of Dislocation-Mediated Plasticity in Ni Single Crystals:Molecular Dynamics Simulations in Journal of Nanomaterials , 2009.Google Scholar
[3] Zhu, Ting and Li, Ju, Ultra-strength materials in Progress in Materials Science , 55 (2010).Google Scholar
[4] Ackland, G. J., D’Mellow, K., Daraszewicz, S. L., Hepburn, D. J., Uhrin, M. and Stratford, K. Computer Physics Communications (submitted) http://code.google.com/p/moldy/ Google Scholar
[5] Hepburn, D.J., Ackland, G.J. and Olsson, P., Rescaled potentials for transition metal solutes in alpha-iron in Phil.Mag , 89 (2009).Google Scholar
[6] AKoh, S.J. and Lee, H.P., Molecular dynamics simulation of size and strain rate dependent mechanical response of FCC metallic nanowires in Nanotechnology , 17 (2006).Google Scholar
[7] Pastor-Abia, L., Caturla, M. J., SanFabian, E., Chiappe, G., and Louis, E., On the stressstrain curves in gold and aluminum nanowires in Phys. Status Solidi C , 6 (2009).Google Scholar
[8] Verlet, L., Computer “Experiments” on Classical Fluids. I. Thermodynamical Properties of Lennard-Jones Molecules in Phys. Rev. , 159 (1967).Google Scholar