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 language | English (US) |
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Pages (from-to) | 621-636 |
Number of pages | 16 |
Journal | Experimental Mechanics |
Volume | 63 |
Issue number | 4 |
DOIs | |
State | Published - Apr 2023 |
Externally published | Yes |
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