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05:04
Determining the Mechanical Strength of Ultra-Fine-Grained Metals
Published on: November 22, 2021
Nanoscale anisotropic plastic deformation in single crystal aragonite
C Kearney1, Z Zhao, B J F Bruet
1Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Physical Review Letters
|August 16, 2006
Summary
Single-crystal aragonite exhibits anisotropic elastic-plastic behavior at the nanoscale. Dislocation nucleation and slip system plasticity were observed using nanoindentation and atomic force microscopy.
Area of Science:
- Materials Science
- Geophysics
- Nanotechnology
Background:
- Understanding the mechanical properties of single crystals is crucial for materials science.
- Aragonite, a polymorph of calcium carbonate, is a significant biomineral and rock-forming mineral.
Purpose of the Study:
- To investigate the nanoscale anisotropic elastic-plastic behavior of single-crystal aragonite.
- To identify the active slip systems governing plasticity in aragonite.
Main Methods:
- Nanoindentation experiments were performed on single-crystal aragonite.
- Tapping mode atomic force microscopy (AFM) was used for high-resolution surface imaging.
- A finite element crystal plasticity model was developed to simulate the mechanical response.
Main Results:
- Force-depth curves showed load plateaus, indicating dislocation nucleation.
- Distinct slip bands and pileup lobes were observed in residual indentation impressions.
- The {110}<001> slip system family and other specific systems were identified as dominant.
Conclusions:
- The study elucidates the anisotropic plastic deformation mechanisms in single-crystal aragonite at the nanoscale.
- Nanoindentation combined with modeling provides insights into mineral plasticity and deformation mechanisms.
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