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What is behind the inverse Hall–Petch effect in nanocrystalline materials?

✍ Scribed by C.E. Carlton; P.J. Ferreira

Publisher: Elsevier Science
Year: 2007
Tongue: English
Weight: 456 KB
Volume: 55
Category: Article
ISSN: 1359-6454
DOI: 10.1016/j.actamat.2007.02.021

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✦ Synopsis

An inverse Hall-Petch effect has been observed for nanocrystalline materials by a large number of researchers. This effect implies that nanocrystalline materials get softer as grain size is reduced below a critical value. Postulated explanations for this behavior include dislocation-based models, diffusion-based models, grain-boundary-shearing models and two-phase-based models. In this paper, we report an explanation for the inverse Hall-Petch effect based on the statistical absorption of dislocations by grain boundaries, showing that the yield strength is dependent on strain rate and temperature and deviates from the Hall-Petch relationship below a critical grain size.

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