Abnormal stress drop at the yield point of aluminum nanowires: A molecular dynamics study

L. Pastor-Abia, M. J. Caturla, E. SanFabián, G. Chiappe, and E. Louis
Phys. Rev. B 83, 165441 – Published 27 April 2011
PDFHTMLExport Citation

Abstract

Molecular dynamics (MD) and experimental data indicate that the stress at the yield point of uniaxially stretched nanowires suffers a sudden large drop (D). In addition, nanowires show a yield strength (YS) significantly higher than that of bulk material. In this work, aiming to identify the parameters characterizing the nanowire that produce these effects, MD simulations are carried out at low temperature (0.5 K) on defect-free aluminum nanowires stretched along the (100) direction. Nanowires are characterized by the aspect ratio and the average coordination. The results can explain neither the absence of the drop in bulk material nor its much lower YS: both yield strength and drop increase logarithmically with the aspect ratio and linearly as the average coordination tends to its bulk value. Increasing the testing temperature smoothes the stress-strain curve and significantly reduces the YS, but does not eliminate the drop whose relative value D/YS remains practically constant. Introducing vacancies reduces both the yield strength and the drop. A detailed analysis of the atomic positions reveals a strong necking at the yield point of defect-free nanowires (absent when vacancies are introduced) that may surely be the cause of the drop.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
1 More
  • Received 23 December 2010

DOI:https://doi.org/10.1103/PhysRevB.83.165441

©2011 American Physical Society

Authors & Affiliations

L. Pastor-Abia1, M. J. Caturla1,2, E. SanFabián1,3,4, G. Chiappe1,2, and E. Louis1,2,4

  • 1Instituto Universitario de Materiales de Alicante (IUMA),Universidad de Alicante, San Vicente del Raspeig, E-03690 Alicante, Spain
  • 2Departamento de Física Aplicada, Universidad de Alicante, San Vicente del Raspeig, E-03690 Alicante, Spain
  • 3Departamento de Química Física, Universidad de Alicante, San Vicente del Raspeig, E-03690 Alicante, Spain
  • 4Unidad Asociada of the “Consejo Superior de Investigaciones Científicas, ”Universidad de Alicante, San Vicente del Raspeig, E-03690 Alicante, Spain

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 83, Iss. 16 — 15 April 2011

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×