Micro-mechanisms of shear deformation during high-pressure torsion of equiatomic FeMnNi medium entropy alloy.
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| Title: | Micro-mechanisms of shear deformation during high-pressure torsion of equiatomic FeMnNi medium entropy alloy. |
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| Authors: | Jha, Saumya Ranjan1 (AUTHOR), Gurao, N. P.1 (AUTHOR), Biswas, Krishanu1 (AUTHOR) kbiswas@iitk.ac.in |
| Source: | Journal of Materials Science. Apr2025, Vol. 60 Issue 15, p6688-6714. 27p. |
| Subjects: | Dislocation nucleation, Shear (Mechanics), Crystal grain boundaries, Grain refinement, Strain rate |
| Abstract: | A FeMnNi equiatomic medium entropy alloy was subjected to high-pressure torsion up to 5 turns under 2 GPa pressure at room temperature to achieve wide range of microstructures comprising of heterogeneous sub-microcrystalline structures to uniform nanocrystalline grains as a function of strain. Heterogeneous intragranular deformation caused by the operation of octahedral and partial slip systems causes rapid grain fragmentation without significant change in aspect ratio. The grain size was reduced from nearly 26 μm, as measured by EBSD, to approximately 59 nm after five turns, as determined by TEM, accompanied by a significant increase in hardness after the first turn, with saturation observed up to five turns. Nanoindentation experiments indicated that the improvement in strength was accompanied with substantial plasticity indicated by the plasticity index Wp/Wt during nanoindentation unloading cycle. This is followed by a decrease in strain rate sensitivity and marginal decrease in activation volume till a shear strain of about εvm ≈ 29, after which both remain almost constant indicating a steady state of microstructural refinement. Microstructural analyses, including EBSD and TEM, confirmed that grain subdivision occurs through dislocation rearrangement, leading to the formation of low-angle grain boundaries that progressively transform to high-angle grain boundaries contributing to grain size refinement by grain subdivision with the increase in strain. The process of grain refinement does not involve nucleation of dislocation free grains as observed for classical discontinuous recrystallization and is attributed to continuous dynamic recrystallization (CDRX) or extended dynamic recovery. Thus, the FeMnNi medium entropy alloy exhibits scope for microstructural engineering in the ultrafine and nanocrystalline regime to achieve optimum combination of strength and ductility. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Materials Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Header | DbId: egs DbLabel: Engineering Source An: 184746989 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Micro-mechanisms of shear deformation during high-pressure torsion of equiatomic FeMnNi medium entropy alloy. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Jha%2C+Saumya+Ranjan%22">Jha, Saumya Ranjan</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Gurao%2C+N%2E+P%2E%22">Gurao, N. P.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Biswas%2C+Krishanu%22">Biswas, Krishanu</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> kbiswas@iitk.ac.in</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Materials+Science%22">Journal of Materials Science</searchLink>. Apr2025, Vol. 60 Issue 15, p6688-6714. 27p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Dislocation+nucleation%22">Dislocation nucleation</searchLink><br /><searchLink fieldCode="DE" term="%22Shear+%28Mechanics%29%22">Shear (Mechanics)</searchLink><br /><searchLink fieldCode="DE" term="%22Crystal+grain+boundaries%22">Crystal grain boundaries</searchLink><br /><searchLink fieldCode="DE" term="%22Grain+refinement%22">Grain refinement</searchLink><br /><searchLink fieldCode="DE" term="%22Strain+rate%22">Strain rate</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: A FeMnNi equiatomic medium entropy alloy was subjected to high-pressure torsion up to 5 turns under 2 GPa pressure at room temperature to achieve wide range of microstructures comprising of heterogeneous sub-microcrystalline structures to uniform nanocrystalline grains as a function of strain. Heterogeneous intragranular deformation caused by the operation of octahedral and partial slip systems causes rapid grain fragmentation without significant change in aspect ratio. The grain size was reduced from nearly 26 μm, as measured by EBSD, to approximately 59 nm after five turns, as determined by TEM, accompanied by a significant increase in hardness after the first turn, with saturation observed up to five turns. Nanoindentation experiments indicated that the improvement in strength was accompanied with substantial plasticity indicated by the plasticity index Wp/Wt during nanoindentation unloading cycle. This is followed by a decrease in strain rate sensitivity and marginal decrease in activation volume till a shear strain of about εvm ≈ 29, after which both remain almost constant indicating a steady state of microstructural refinement. Microstructural analyses, including EBSD and TEM, confirmed that grain subdivision occurs through dislocation rearrangement, leading to the formation of low-angle grain boundaries that progressively transform to high-angle grain boundaries contributing to grain size refinement by grain subdivision with the increase in strain. The process of grain refinement does not involve nucleation of dislocation free grains as observed for classical discontinuous recrystallization and is attributed to continuous dynamic recrystallization (CDRX) or extended dynamic recovery. Thus, the FeMnNi medium entropy alloy exhibits scope for microstructural engineering in the ultrafine and nanocrystalline regime to achieve optimum combination of strength and ductility. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Materials Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1007/s10853-025-10824-7 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 27 StartPage: 6688 Subjects: – SubjectFull: Dislocation nucleation Type: general – SubjectFull: Shear (Mechanics) Type: general – SubjectFull: Crystal grain boundaries Type: general – SubjectFull: Grain refinement Type: general – SubjectFull: Strain rate Type: general Titles: – TitleFull: Micro-mechanisms of shear deformation during high-pressure torsion of equiatomic FeMnNi medium entropy alloy. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Jha, Saumya Ranjan – PersonEntity: Name: NameFull: Gurao, N. P. – PersonEntity: Name: NameFull: Biswas, Krishanu IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 04 Text: Apr2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 00222461 Numbering: – Type: volume Value: 60 – Type: issue Value: 15 Titles: – TitleFull: Journal of Materials Science Type: main |
| ResultId | 1 |
