Disclination dipoles are the Holy Grail for high temperature superplasticity in ceramics

A model for high-temperature plasticity of polycrystals controlled by disclination dipoles is proposed that predict a parabolic dependence of the strain rate versus the applied stress. The presence of a precise stationary disclination density explains the origin of plasticity without microstructural...

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Bibliographic Details
Published in:Scripta materialia 2020-08, Vol.185, p.21-24
Main Authors: Moshtaghioun, Bibi Malmal, Bejarano-Palma, José Antonio, García, Diego Gómez
Format: Article
Language:English
Subjects:
Ceramics
Disclination dipoles
Super-plasticity
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Summary:A model for high-temperature plasticity of polycrystals controlled by disclination dipoles is proposed that predict a parabolic dependence of the strain rate versus the applied stress. The presence of a precise stationary disclination density explains the origin of plasticity without microstructural invariance, commonly known as superplasticity. The disclination mechanism is universal, although other processes, such as dislocation glide, are superposed to this one in many systems such as metals or metallic alloys. While, in ceramics it is likely to be the only operative mechanism. Activation of disclination dipoles is a necessary condition for plasticity and sufficient one for superplastic yielding. [Display omitted]
ISSN:1359-6462
1872-8456
DOI:10.1016/j.scriptamat.2020.03.049