Abstract
Contrary to the dislocation-driven ‘smaller-is-stronger’ size-effect in nanocrystals, the size-dependence of strength in deformation twinning, another carrier of plasticity, still lacks universal understanding. Deformation twinning enables pseudoplastic strain of >5% in a shape memory ceramic (ZrHfO4)x (YTaO4)1−x. We use diffraction methods, microstructure analysis, and in-situ nanomechanical experiments to uncover contributing factors to the competition between twinning and slip in these submicron-sized ionic crystals, revealing power-law scaling of strength with size for both mechanisms. The significant twinning size-dependence was found to follow a superimposed power-law with exponent of -1, identical to that in metals. These findings unveil the universality of the superimposed power-law size-effect for twinning in single-crystals and provide new insights on deformability of ceramics and microstructure-driven nano-plasticity.
Original language | English (US) |
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Article number | 101124 |
Journal | Extreme Mechanics Letters |
Volume | 42 |
DOIs | |
State | Published - Jan 2021 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2020 Elsevier Ltd
Keywords
- Crystallography
- Deformation twinning
- In-situ nanomechanics
- Plasticity
- Shape memory ceramics