Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-19T02:50:03.407Z Has data issue: false hasContentIssue false
  • English
  • Français

A method for analyzing nanomechanical deformation of nanocrystalline Ni at higher timesteps than is possible in classical molecular dynamics

Published online by Cambridge University Press:  26 February 2011

Vikas Tomar
Vikas Tomar*
Affiliation:
[email protected], University of Notre Dame, Arospace and Mechanical Engineering, 376 Fitzpatrick Hall, Notre Dame, IN, 46556, United States, 001-574-631-7826, 001-574-631-8341
Get access

Abstract

A majority of computational mechanical analyses of nanocrystalline materials have been carried out using classical molecular dynamics (MD). Due to the fundamental reason that the MD simulations must resolve atomic level vibrations, they cannot be carried out at the timescale of the order of microseconds. Additionally, MD simulations have to be carried out at very high loading rates (∼108 s−1) rarely observed in experiments. In this investigation a modified Hybrid Monte Carlo (HMC) method that can be used to analyze time-dependent (strain rate dependent) atomistic mechanical deformation of nanocrystalline structures at higher timescales than currently possible using MD is established. In this method there is no restriction on the size of MD timestep except that it must be such that to ensure a reasonable acceptance rate between consecutive Monte-Carlo (MC) time-steps. For the purpose of comparison HMC analyses of a nanocrystalline Ni sample at a strain rate of 109 s−1 with three different timesteps, viz. 2 fs, 4fs, and 8 fs, are compared with the analyses based on MD simulations at the same strain rate and a MD timestep of 2 fs. MD simulations of nanocrystalline Ni reproduce the defect nucleation and propagation results as well as strength values reported in the literature. In addition, HMC with timestep of 8 fs correctly reproduces defect formation and stress-strain response observed in the case of MD simulations with permissible timestep of 2 fs (for the interatomic potential used 2 fs is the highest MD timestep). Simulation time analyses show that by using HMC a saving of the order of 4 can be achieved bringing the atomistic analyses closer to the continuum timescales.

Keywords

nanoscalesimulationpolycrystal
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 978: Symposium GG – Multiscale Modeling of Materials , 2006 , 0978-GG06-03
Copyright
Copyright © Materials Research Society 2007

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

1. Yamakov, V., Wolf, D., Phillpot, S.R., and Gleiter, H., Acta Materialia, 2002. 50: p. 5005–5020.Google Scholar
2. Voter, A.F., Montalenti, F., and Germann, T.C., Annu. Rev. Mater. Res., 2002. 32: p. 321–346.Google Scholar
3. Mehlig, B., Heerman, D.W., and Forrest, B.M., Phys. Rev. B, 1992. 45(2): p. 680–685.Google Scholar
4. Tomar, V. and Zhou, M., Phys Rev B, 2006. 73: p. 174116 (1–16).Google Scholar
5. Mishin, Y., Farkas, D., Mehl, M.J., and Papaconstantopoulos, D.A., Phys. Rev. B, 1999. 59(5): p. 3393–3407.Google Scholar
6. Berne, B.J. and Straub, J.E., Current Opinion in Structural Biology, 1997. 7: p. 1181–189.Google Scholar
7. Clamp, M.E., Baker, P.G., Stirling, C.J., and Brass, A., J. Computational Chemistry, 1994. 15(8): p. 838–846.Google Scholar
8. Melchionna, S., Ciccotti, G., and Holian, B.L., Mol. Phys., 1993. 78(3): p. 533–544.Google Scholar
9. Tomar, V. and Zhou, M., Appl. Phys. Lett., 2006. 88: p. 233107 (1–3).Google Scholar
10. Gross, D. and Li, M., Appl. Phys. Lett., 2002. 80(5): p. 746–748.Google Scholar
11. Van Swygenhoven, H. and Caro, A., Phys. Rev. B, 1998. 58(17): p. 11246–11251.Google Scholar
12. Tomar, V. and Zhou, M., 2006, Journal of the Mechanics and Physics of Solids, doi:10.1016/j.jmps.2006.10.00.Google Scholar