Size-dependence of zirconia-based ceramics via deformation twinning

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 (Zr...

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Bibliographic Details
Published in:Extreme Mechanics Letters 2021-01, Vol.42 (C), p.101124, Article 101124
Main Authors: Zhang, H., Gu, H., Jetter, J., Quandt, E., James, R.D., Greer, J.R.
Format: Article
Language:English
Subjects:
Crystallography
Deformation twinning
In-situ nanomechanics
Plasticity
Shape memory ceramics
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Summary: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.
ISSN:2352-4316
2352-4316
DOI:10.1016/j.eml.2020.101124