Orientation-dependence of incipient plasticity in a coarse-grained Mg revealed by nanoindentation pop-ins
The nanoindentation pop-in behaviors of 13 grains with diverse crystallographic orientations were analysed using a coarse-grained Mg-2 wt.% Gd alloy. Within nanoscale stressed volumes within all grains, the converted shear stresses for the first pop-in, calculated using the indentation Schmid factor...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
KeAi Communications Co., Ltd.
2025-06-01
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| Series: | Journal of Magnesium and Alloys |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2213956725001227 |
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| Summary: | The nanoindentation pop-in behaviors of 13 grains with diverse crystallographic orientations were analysed using a coarse-grained Mg-2 wt.% Gd alloy. Within nanoscale stressed volumes within all grains, the converted shear stresses for the first pop-in, calculated using the indentation Schmid factor, ranged from 1 to 1.3 GPa, consistent with theoretical predictions for dislocation nucleation in Mg. The estimated activation volume of the first pop-in was approximately 27–40 ų (involving about ∼2 atoms), aligning with reported atomistic simulations of the surface dislocation semi-loop nucleation. While indented near the ⟨c⟩-axis, grains exhibit higher first pop-in loads and successive pop-ins, implying the possibility of a cross-slip nucleation mechanism to accommodate ⟨c⟩-axis deformation. |
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| ISSN: | 2213-9567 |