Abstract

The compressive plastic strength of nanosized single-crystal metallic pillars is known to depend on their diameter D. Herein, the role of pillar height h is analyzed instead, and the suppression of the generalized crystal plasticity below a critical value hCR is observed. Novel in situ compression tests on regular pillars as well as nanobuttons, that is, pillars with h<hCR, show that the latter are much harder, withstanding stresses >2 GPa. A statistical model that holds for both pillars and buttons is formulated. Owing to their superhard nature, the nanobuttons examined here underline with unprecedented resolution the extrinsic effects-often overlooked-that naturally arise during testing when the Saint-Venant assumption ceases to be accurate. The bias related to such effects is identified in the test data and removed when possible. Finally, continuous hardening is observed to occur under increasing stress level, in analogy to reports on nanoparticles. From a metrological standpoint the results expose some difficulties in nanoscale testing related to current methodology and technology. The implications of the analysis of extrinsic effects go beyond nanobuttons and extend to nano-/ microelectromechanical system design and nanomechanics in general.

Original languageEnglish (US)
Pages (from-to)528-536
Number of pages9
JournalSmall
Volume6
Issue number4
DOIs
StatePublished - Feb 22 2010

Keywords

  • Crystal plasticity
  • Mechanical properties
  • Nanobuttons
  • Nanocharacterization
  • Pillars

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)

Fingerprint Dive into the research topics of 'Superhard nanobuttons: Constraining crystal plasticity and dealing with extrinsic effects at the nanoscale'. Together they form a unique fingerprint.

  • Cite this