Seventy years of Hall-Petch, ninety years of superplasticity and a generalized approach to the effect of grain size on flow stress
Seventy years of Hall-Petch, ninety years of superplasticity and a generalized approach to the effect of grain size on flow stress
The grain size, and therefore the grain boundary density, is known to play a major role in the flow stress of metallic materials. A linear relationship to the inverse of the square root of the grain size was identified about 70 years ago giving rise to the well-established Hall-Petch grain refinement strengthening effect. Nevertheless, grain refinement softening is known to take place at high homologous temperatures and both effects have been given separate treatments. A recent model showed that a general relationship can explain both the Hall-Petch strengthening effect at low temperatures and superplasticity at high temperatures. The present review discusses recent advances in structural and mechanical characterization to provide an updated analysis of trends observed in the relationship between the grain size and the flow stress. The model of grain boundary sliding is evaluated using multiple sets of data in the literature and a general description is provided for the transition between grain refinement hardening and grain refinement softening. The analysis incorporate data from over 30 different metals and alloys with different grain sizes and after testing at different strain rates and temperatures. Data from molecular dynamic simulations are also included and show supporting evidence to the model of grain boundary sliding. The thermal contribution of the grain size strengthening and threshold stress is discussed including the trends observed in the strain rate sensitivity of fine-grained materials.
deformation mechanisms, grain boundary sliding, hall-petch, mechanical properties, superplasticity, Superplasticity, Deformation mechanisms, Hall-Petch, Mechanical properties, Grain boundary sliding
B. Figueiredo, Roberto
43e41579-1772-4194-baab-a1d7f9814f6a
Kawasaki, Megumi
944ba471-eb78-46db-bfb7-3f0296d9ef6d
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
28 April 2023
B. Figueiredo, Roberto
43e41579-1772-4194-baab-a1d7f9814f6a
Kawasaki, Megumi
944ba471-eb78-46db-bfb7-3f0296d9ef6d
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
B. Figueiredo, Roberto, Kawasaki, Megumi and Langdon, Terence G.
(2023)
Seventy years of Hall-Petch, ninety years of superplasticity and a generalized approach to the effect of grain size on flow stress.
Progress in Materials Science, 137 (8), [101131].
(doi:10.1016/j.pmatsci.2023.101131).
Abstract
The grain size, and therefore the grain boundary density, is known to play a major role in the flow stress of metallic materials. A linear relationship to the inverse of the square root of the grain size was identified about 70 years ago giving rise to the well-established Hall-Petch grain refinement strengthening effect. Nevertheless, grain refinement softening is known to take place at high homologous temperatures and both effects have been given separate treatments. A recent model showed that a general relationship can explain both the Hall-Petch strengthening effect at low temperatures and superplasticity at high temperatures. The present review discusses recent advances in structural and mechanical characterization to provide an updated analysis of trends observed in the relationship between the grain size and the flow stress. The model of grain boundary sliding is evaluated using multiple sets of data in the literature and a general description is provided for the transition between grain refinement hardening and grain refinement softening. The analysis incorporate data from over 30 different metals and alloys with different grain sizes and after testing at different strain rates and temperatures. Data from molecular dynamic simulations are also included and show supporting evidence to the model of grain boundary sliding. The thermal contribution of the grain size strengthening and threshold stress is discussed including the trends observed in the strain rate sensitivity of fine-grained materials.
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Accepted/In Press date: 13 April 2023
e-pub ahead of print date: 20 April 2023
Published date: 28 April 2023
Additional Information:
Funding Information:
This work was supported by CNPq (Grant # 302445/2018-8 ) and FAPEMIG (Grant TEC-PPM-00324-17 ) (RBF), by the National Science Foundation of the United States under Grant No. CMMI-2051205 (MK) and by the European Research Council under ERC Grant Agreement No. 267464-SPDMETALS (TGL).
Keywords:
deformation mechanisms, grain boundary sliding, hall-petch, mechanical properties, superplasticity, Superplasticity, Deformation mechanisms, Hall-Petch, Mechanical properties, Grain boundary sliding
Identifiers
Local EPrints ID: 478564
URI: http://eprints.soton.ac.uk/id/eprint/478564
ISSN: 0079-6425
PURE UUID: 7068c715-0409-4514-8a40-af26996abf84
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Date deposited: 04 Jul 2023 18:03
Last modified: 06 Jun 2024 01:40
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Contributors
Author:
Roberto B. Figueiredo
Author:
Megumi Kawasaki
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