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Phys. Rev. Lett. 85, 2332–2335 (2000)

Elastic Instability of Grain Boundaries and the Physical Origin of Superplasticity

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Miguel Lagos
Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile

Received 3 March 2000; published in the issue dated 11 September 2000

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Matter between contiguous crystallites is assimilated to a thin elastic plate immersed in a different elastic medium. It is shown that a shear stress exceeding a critical value should corrugate the boundary and induce periodic normal stress fields in the two adjacent crystal surfaces, which cause motion of vacancies in closed loops between the two crystals. The consequent cyclic transport of atoms in the opposite sense determines crystal sliding at a temperature dependent relative speed. Most of the phenomenology of superplastic allows follows in a quantitative manner.

© 2000 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.85.2332
DOI:
10.1103/PhysRevLett.85.2332
PACS:
62.20.Fe, 46.70.De, 61.50.Ks, 61.72.Mm