The Hall–Petch and inverse Hall–Petch relations and the hardness of nanocrystalline metals
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Publication Date
2020-03-01Journal Title
Journal of Materials Science
ISSN
0022-2461
Publisher
Springer Nature
Volume
55
Issue
7
Pages
2661-2681
Type
Article
This Version
VoR
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Naik, S., & Walley, S. (2020). The Hall–Petch and inverse Hall–Petch relations and the hardness of nanocrystalline metals. Journal of Materials Science, 55 (7), 2661-2681. https://doi.org/10.1007/s10853-019-04160-w
Abstract
We review some of the factors that influence the hardness of polycrystalline materials with grain-sizes less than 1 µm. The fundamental physical mechanisms that govern the hardness of nanocrystalline materials are discussed. The recently proposed dislocation curvature model for grain size dependent strengthening and the 60-year old Hall-Petch relationship are compared. For grains less than 30 nm in size, there is evidence for a transition from dislocation-based plasticity to grain boundary sliding, rotation or diffusion as the main mechanism responsible for hardness. The evidence surrounding the inverse Hall-Petch phenomenon is found to be inconclusive due to processing artefacts, grain growth effects and errors associated with the conversion of hardness to yield strength in nanocrystalline materials.
Identifiers
External DOI: https://doi.org/10.1007/s10853-019-04160-w
This record's URL: https://www.repository.cam.ac.uk/handle/1810/299120