Local, atomic-level elastic strain measurements of metallic glass thin films by electron diffraction

C. Ebner, R. Sarkar, Jagannathan Rajagopalan, C. Rentenberger

Research output: Contribution to journalArticle

  • 4 Citations

Abstract

A novel technique is used to measure the atomic-level elastic strain tensor of amorphous materials by tracking geometric changes of the first diffuse ring of selected area electron diffraction patterns (SAD). An automatic procedure, which includes locating the centre and fitting an ellipse to the diffuse ring with sub-pixel precision is developed for extracting the 2-dimensional strain tensor from the SAD patterns. Using this technique, atomic-level principal strains from micrometre-sized regions of freestanding amorphous Ti0.45Al0.55 thin films were measured during in-situ TEM tensile deformation. The thin films were deformed using MEMS based testing stages that allow simultaneous measurement of the macroscopic stress and strain. The calculated atomic-level principal strains show a linear dependence on the applied stress, and good correspondence with the measured macroscopic strains. The calculated Poisson's ratio of 0.23 is reasonable for brittle metallic glasses. The technique yields a strain accuracy of about 1×10-4 and shows the potential to obtain localized strain profiles/maps of amorphous thin film samples.

LanguageEnglish (US)
Pages51-58
Number of pages8
JournalUltramicroscopy
Volume165
DOIs
StatePublished - Jun 1 2016

Fingerprint

strain measurement
Strain measurement
Metallic glass
metallic glasses
Electron diffraction
electron diffraction
Thin films
thin films
tensors
tensile deformation
rings
amorphous materials
ellipses
Poisson ratio
microelectromechanical systems
micrometers
Amorphous films
diffraction patterns
pixels
Tensors

Keywords

  • Amorphous alloy
  • Electron diffraction pattern
  • In-situ TEM
  • Metallic Glass
  • Thin Films

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Instrumentation
  • Electronic, Optical and Magnetic Materials

Cite this

Local, atomic-level elastic strain measurements of metallic glass thin films by electron diffraction. / Ebner, C.; Sarkar, R.; Rajagopalan, Jagannathan; Rentenberger, C.

In: Ultramicroscopy, Vol. 165, 01.06.2016, p. 51-58.

Research output: Contribution to journalArticle

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