Gao, J., Jiang, S., Zhang, H. et al. (11 more authors) (2021) Facile route to bulk ultrafine-grain steels for high strength and ductility. Nature, 590 (7845). pp. 262-267. ISSN 0028-0836
Abstract
Steels with sub-micrometre grain sizes usually possess high toughness and strength, which makes them promising for lightweighting technologies and energy-saving strategies. So far, the industrial fabrication of ultrafine-grained (UFG) alloys, which generally relies on the manipulation of diffusional phase transformation, has been limited to steels with austenite-to-ferrite transformation1,2,3. Moreover, the limited work hardening and uniform elongation of these UFG steels1,4,5 hinder their widespread application. Here we report the facile mass production of UFG structures in a typical Fe–22Mn–0.6C twinning-induced plasticity steel by minor Cu alloying and manipulation of the recrystallization process through the intragranular nanoprecipitation (within 30 seconds) of a coherent disordered Cu-rich phase. The rapid and copious nanoprecipitation not only prevents the growth of the freshly recrystallized sub-micrometre grains but also enhances the thermal stability of the obtained UFG structure through the Zener pinning mechanism6. Moreover, owing to their full coherency and disordered nature, the precipitates exhibit weak interactions with dislocations under loading. This approach enables the preparation of a fully recrystallized UFG structure with a grain size of 800 ± 400 nanometres without the introduction of detrimental lattice defects such as brittle particles and segregated boundaries. Compared with the steel to which no Cu was added, the yield strength of the UFG structure was doubled to around 710 megapascals, with a uniform ductility of 45 per cent and a tensile strength of around 2,000 megapascals. This grain-refinement concept should be extendable to other alloy systems, and the manufacturing processes can be readily applied to existing industrial production lines.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 The Author(s). This is an author-produced version of a paper subsequently published in Nature. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Funding Information: | Funder Grant number Engineering and Physical Sciences Research Council EP/L025213/1 Engineering and Physical Sciences Research Council EP/R00661X/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 03 Mar 2021 14:33 |
Last Modified: | 10 Aug 2021 00:38 |
Status: | Published |
Publisher: | Springer Science and Business Media LLC |
Refereed: | Yes |
Identification Number: | 10.1038/s41586-021-03246-3 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:171771 |