Dislocation versus grain boundary strengthening in SPD processed metals: non-causal relation between grain size and strength of deformed polycrystals
Dislocation versus grain boundary strengthening in SPD processed metals: non-causal relation between grain size and strength of deformed polycrystals
In metals that are heavily cold deformed, for instance by a severe plastic deformation process, significant strengthening is caused by the high density of defects such as grain boundaries and dislocations. In this work a model for volume-averaged dislocation and grain boundary (GB) creation is used to show that unless significant annihilation of defects post deformation occurs, the dislocation densities and GB densities in the deformed material are closely correlated. The dislocation strengthening effect thus shows a strong correlation with GB strengthening, and correlation of strength or hardness with d−1/2, where d is the grain size, as in a Hall-Petch type plot, can not be taken as an indication that GB strengthening dominates. Instead, in many SPD processed metals and alloys, dislocation strengthening is the dominant strengthening effect, even though a Hall-Petch type plot shows a good linear correlation.
severe plastic deformation (SPD), dislocations, recovery, hardness, grain size, SPD, Severe plastic deformation
42-45
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
29 September 2017
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
Starink, M.J.
(2017)
Dislocation versus grain boundary strengthening in SPD processed metals: non-causal relation between grain size and strength of deformed polycrystals.
Materials Science and Engineering: A, 705, .
(doi:10.1016/j.msea.2017.08.069).
Abstract
In metals that are heavily cold deformed, for instance by a severe plastic deformation process, significant strengthening is caused by the high density of defects such as grain boundaries and dislocations. In this work a model for volume-averaged dislocation and grain boundary (GB) creation is used to show that unless significant annihilation of defects post deformation occurs, the dislocation densities and GB densities in the deformed material are closely correlated. The dislocation strengthening effect thus shows a strong correlation with GB strengthening, and correlation of strength or hardness with d−1/2, where d is the grain size, as in a Hall-Petch type plot, can not be taken as an indication that GB strengthening dominates. Instead, in many SPD processed metals and alloys, dislocation strengthening is the dominant strengthening effect, even though a Hall-Petch type plot shows a good linear correlation.
Text
Starink MSEA 2017
- Accepted Manuscript
More information
Accepted/In Press date: 17 August 2017
e-pub ahead of print date: 18 August 2017
Published date: 29 September 2017
Keywords:
severe plastic deformation (SPD), dislocations, recovery, hardness, grain size, SPD, Severe plastic deformation
Identifiers
Local EPrints ID: 414040
URI: http://eprints.soton.ac.uk/id/eprint/414040
ISSN: 0921-5093
PURE UUID: 233de905-c4f0-4a37-a1e7-9b383f8b4035
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Date deposited: 13 Sep 2017 16:31
Last modified: 16 Mar 2024 05:43
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