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Determining the Mechanical Strength of Ultra-Fine-Grained Metals
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Determining the Volume Expansion at Grain Boundaries Using Extended Energy-Loss Fine Structure Analysis
1Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville, VA 22904-4745, USA.
Summary
Extended Energy-Loss Fine Structure (EXELFS) analysis revealed that grain boundary energy correlates with normal volume expansion. This study confirms EXELFS as a valuable technique for measuring volume expansion at grain boundaries.
Area of Science:
- Materials Science
- Solid-State Physics
- Electron Microscopy
Background:
- Grain boundaries (GBs) significantly influence material properties.
- A known correlation exists between GB energy and normal volume expansion.
- Understanding GBs is crucial for material design and performance.
Purpose of the Study:
- To experimentally determine volume expansion at GBs using EXELFS.
- To investigate the relationship between GB energy and volume expansion.
- To validate EXELFS as a technique for measuring normal volume expansion.
Main Methods:
- Utilized extended energy-loss fine structure (EXELFS) analysis in a scanning/transmission electron microscope.
- Measured nearest-neighbor (n.n.) distances with nanometer spatial resolution.
- Employed complementary plasmon energy profiles and valence electron energy-loss spectroscopy.
Main Results:
- EXELFS analysis showed increased average n.n. distances at GBs with higher GB energy.
- Total volume expansion at GBs agreed well with other experimental techniques.
- GB energy correlates with decreased electron density and increased specific volume expansion at the GB.
Conclusions:
- EXELFS is a reliable technique for measuring normal volume expansion at GBs.
- GB energy is linked to electron density and volume expansion.
- This research provides insights into the fundamental properties of grain boundaries.
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