Surface roughness imparts tensile ductility to nanoscale metallic glasses

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

13 Scopus Citations
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Author(s)

  • Sara Adibi
  • Paulo S. Branicio
  • Rachel Liontas
  • David Z. Chen
  • Julia R. Greer
  • Shailendra P. Joshi

Detail(s)

Original languageEnglish
Pages (from-to)88-95
Journal / PublicationExtreme Mechanics Letters
Volume5
Online published28 Aug 2015
Publication statusPublished - Dec 2015
Externally publishedYes

Abstract

Experiments show an intriguing brittle-to-ductile transition on size reduction on nanoscale metallic glasses (MGs). Here we demonstrate that such phenomena is linked to a fundamental characteristic size effect in the failure mode under tensile loading. Large-scale molecular dynamics simulations reveal that nanoscaled MGs with atomistically smooth surfaces exhibit catastrophic failure via sharp, localized shear band propagation. In contrast, nanosized specimens with surface imperfections exhibit a clear transition from shear banding to necking instability above a critical roughness ratio of ξ~ 1/20, defined as the ratio between the average surface imperfection size and sample diameter. The observed brittle-to-ductile transition that emerges in nanosized MGs deformed at room temperature can be strongly attributed to this roughness argument. In addition, the results suggest that the suppression of brittle failure may be scale-free and be realizable on length scales much beyond those considered here, provided the threshold roughness ratio is exceeded. The fundamental critical roughness ratio demonstrated sheds light on the complex mechanical behavior of amorphous metals and has implications for the application of MGs in nano- and micro-devices.

Research Area(s)

  • Brittle-to-ductile transition, Metallic glasses, Molecular dynamics simulation, Size effect, Surface roughness, Tensile ductility

Citation Format(s)

Surface roughness imparts tensile ductility to nanoscale metallic glasses. / Adibi, Sara; Branicio, Paulo S.; Liontas, Rachel; Chen, David Z.; Greer, Julia R.; Srolovitz, David J.; Joshi, Shailendra P.

In: Extreme Mechanics Letters, Vol. 5, 12.2015, p. 88-95.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal