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

Author(s)
Christian Ebner, R. Sarkar, J. Rajagopalan, C. Rentenberger
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.

Organisation(s)
Physics of Nanostructured Materials
Journal
Ultramicroscopy
Volume
165
Pages
51-58
No. of pages
8
ISSN
0304-3991
DOI
https://doi.org/10.1016/j.ultramic.2016.04.004
Publication date
06-2016
Publication status
Published
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics, 103042 Electron microscopy
Keywords
Amorphous alloy, Electron diffraction pattern, In-situ TEM, Metallic Glass, Thin Films
ASJC Scopus subject areas
Metals and Alloys, Instrumentation
Portal url
https://ucris.univie.ac.at/portal/en/publications/local-atomiclevel-elastic-strain-measurements-of-metallic-glass-thin-films-by-electron-diffraction(c328f777-66d6-4b8a-ab98-bad827709b07).html