The microstructure of as-quenched 12Mn steel.
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| Title: | The microstructure of as-quenched 12Mn steel. |
|---|---|
| Authors: | Kinney, C.C.1 kinney@berkeley.edu, Yi, I.2, Pytlewski, K.R.1, Khachaturyan, A.G.1, Kim, N.J.3, Jr.Morris, J.W.1 |
| Source: | Acta Materialia. Feb2017, Vol. 125, p442-454. 13p. |
| Subjects: | Microstructure, Metal quenching, Steel, Fracture mechanics, Cryogenics, Austenite |
| Abstract: | Fe-12Mn steel has the unique and interesting property that, when quenched to α′ martensite from the austenite phase, it forms an ultrafine grained microstructure that has exceptional resistance to cleavage fracture at cryogenic temperatures. The present research was undertaken to complete the characterization of this microstructure and understand why it forms and why it has such exceptional crack resistance. A combination of EBSD and TEM analysis shows that the microstructure is a dislocated lath martensite in which the laths have the Kurdjumov-Sachs relation to the parent austenite. As in other dislocated lath martensites, the prior austenite grains are divided into packets, each of which contains the 6 (of 24) KS variants that mate with the same { 111 } γ plane. Uniquely, however, the packets are stacks of thin plates that contain all 6 KS variants. The variants within the plate are organized into 3 pair of twinned KS variants that are elongated along their { 112 } α twin planes, rotated 120° from one another, and interwoven to form the 6-variant plate. The ultrafine grains are the laths themselves; twin boundaries between KS variants are known to provide strong barriers to cleavage crack propagation. This unusual microstructure is apparently due to the transformation path; austenite transforms to the hexagonal ε martensite phase before its ultimate transformation to α′ , and the 6-variant plate is the preferred element to minimize elastic energy in a microstructure created by a dominant γ → ε → α ′ transformation path. [ABSTRACT FROM AUTHOR] |
| Copyright of Acta Materialia is the property of Elsevier B.V. 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.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 121051001 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: The microstructure of as-quenched 12Mn steel. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Kinney%2C+C%2EC%2E%22">Kinney, C.C.</searchLink><relatesTo>1</relatesTo><i> kinney@berkeley.edu</i><br /><searchLink fieldCode="AR" term="%22Yi%2C+I%2E%22">Yi, I.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Pytlewski%2C+K%2ER%2E%22">Pytlewski, K.R.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Khachaturyan%2C+A%2EG%2E%22">Khachaturyan, A.G.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Kim%2C+N%2EJ%2E%22">Kim, N.J.</searchLink><relatesTo>3</relatesTo><br /><searchLink fieldCode="AR" term="%22Jr%2EMorris%2C+J%2EW%2E%22">Jr.Morris, J.W.</searchLink><relatesTo>1</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Acta+Materialia%22">Acta Materialia</searchLink>. Feb2017, Vol. 125, p442-454. 13p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Microstructure%22">Microstructure</searchLink><br /><searchLink fieldCode="DE" term="%22Metal+quenching%22">Metal quenching</searchLink><br /><searchLink fieldCode="DE" term="%22Steel%22">Steel</searchLink><br /><searchLink fieldCode="DE" term="%22Fracture+mechanics%22">Fracture mechanics</searchLink><br /><searchLink fieldCode="DE" term="%22Cryogenics%22">Cryogenics</searchLink><br /><searchLink fieldCode="DE" term="%22Austenite%22">Austenite</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Fe-12Mn steel has the unique and interesting property that, when quenched to α′ martensite from the austenite phase, it forms an ultrafine grained microstructure that has exceptional resistance to cleavage fracture at cryogenic temperatures. The present research was undertaken to complete the characterization of this microstructure and understand why it forms and why it has such exceptional crack resistance. A combination of EBSD and TEM analysis shows that the microstructure is a dislocated lath martensite in which the laths have the Kurdjumov-Sachs relation to the parent austenite. As in other dislocated lath martensites, the prior austenite grains are divided into packets, each of which contains the 6 (of 24) KS variants that mate with the same { 111 } γ plane. Uniquely, however, the packets are stacks of thin plates that contain all 6 KS variants. The variants within the plate are organized into 3 pair of twinned KS variants that are elongated along their { 112 } α twin planes, rotated 120° from one another, and interwoven to form the 6-variant plate. The ultrafine grains are the laths themselves; twin boundaries between KS variants are known to provide strong barriers to cleavage crack propagation. This unusual microstructure is apparently due to the transformation path; austenite transforms to the hexagonal ε martensite phase before its ultimate transformation to α′ , and the 6-variant plate is the preferred element to minimize elastic energy in a microstructure created by a dominant γ → ε → α ′ transformation path. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Acta Materialia is the property of Elsevier B.V. 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: 10.1016/j.actamat.2016.12.001 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 13 StartPage: 442 Subjects: – SubjectFull: Microstructure Type: general – SubjectFull: Metal quenching Type: general – SubjectFull: Steel Type: general – SubjectFull: Fracture mechanics Type: general – SubjectFull: Cryogenics Type: general – SubjectFull: Austenite Type: general Titles: – TitleFull: The microstructure of as-quenched 12Mn steel. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Kinney, C.C. – PersonEntity: Name: NameFull: Yi, I. – PersonEntity: Name: NameFull: Pytlewski, K.R. – PersonEntity: Name: NameFull: Khachaturyan, A.G. – PersonEntity: Name: NameFull: Kim, N.J. – PersonEntity: Name: NameFull: Jr.Morris, J.W. IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 02 Text: Feb2017 Type: published Y: 2017 Identifiers: – Type: issn-print Value: 13596454 Numbering: – Type: volume Value: 125 Titles: – TitleFull: Acta Materialia Type: main |
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