Elsevier

Scripta Materialia

Volume 185, August 2020, Pages 21-24
Scripta Materialia

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

https://doi.org/10.1016/j.scriptamat.2020.03.049Get rights and content

Abstract

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.

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Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This work was supported by the Ministerio de Economía y Competitividad (Government of Spain) and FEDER Funds under Grants No. MAT2015-71411-R. BMM wants to acknowledge the support of the Spanish MINECO by means of a “Juan de la Cierva-Incorporación” fellowship during her sabbatical stay in Zaragoza and also the funding by the ‘Junta de Andalucía’ Regional Government through the project P18-RTJ-1972.

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