Creep Characterization of Amorphous SiO2 in the Transmission Electron Microscope Using Digital Image Correlation and Finite Element Analysis

Y. Zhang, Shen J Dillon, J. Lambros

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Amorphous silica (a-SiO2) exhibits creep behavior under electron beam irradiation in the transmission electron microscope (TEM) even at room temperature. This effect is invariably present during in situ TEM microscale mechanical testing of a-SiO2, thus necessitating creep characterization of this material in the TEM environment. Objective: In this paper, we extract creep properties of a-SiO2 during electron beam irradiation induced creep (IIC) by combining experimental measurements with a 2D finite element model (FEM) based on an assumed creep behavior modeled by power creep law. Methods: Micron sized a-SiO2 beam samples deposited with gold nanoparticles are machined by focused ion beam milling and loaded in the TEM via indentation. The applied load-displacement profile at the loading point is recorded by the indenter, while full-field deformation is measured from the TEM images by correlating deformed and undeformed nanoparticle speckle patterns using digital image correlation (DIC). Results: The elastic modulus and creep properties are obtained by solving an inverse problem in the FEM analysis based on the experimentally measured load-displacement data, and are validated by full-field displacement comparisons between FEM results and DIC measurements. Conclusion: FEM and DIC results show good agreement, indicating applicability of the power creep model and the accuracy of extracted creep properties. A linear dependance between creep strain rate and applied stress is derived. Possible error sources from both the experiment and simulation are discussed.

Original languageEnglish (US)
Pages (from-to)621-636
Number of pages16
JournalExperimental Mechanics
Volume63
Issue number4
DOIs
StatePublished - Apr 2023
Externally publishedYes

Keywords

  • Digital image correlation
  • Finite element model
  • Inverse analysis
  • Irradiation induced creep
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Aerospace Engineering
  • Mechanics of Materials
  • Mechanical Engineering

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